physics

d. your resistance to be lower

. You have likely been warned to avoid contact with electrical appliances or even electrical outlets when your hands are wet. Such contact is more dangerous when your hands are wet (vs. dry) because wet hands cause ____. a. the voltage of the circuit to be higher b. the voltage of the circuit to be lower c. your resistance to be higher d. your resistance to be lower e. the current through you to be lower

(3.5 kg) • (1.27 m/s) = 4.445 kg•m/s (3.5 kg) • v Tennis Ball (0.0527 kg) • (1.27 m/s) = 0.06693 kg•m/s (0.0527 kg) • (75 m/s) = 3.9525 kg•m/s Total 4.5119 kg•m/s 4.5119 kg•m/s 4.445 kg•m/s + 0.06693 kg•m/s = (3.5 kg) • v + 3.9525 kg•m/s 4.445 kg•m/s + 0.06693 kg•m/s - 3.9525 kg•m/s = (3.5 kg) • v 0.5594 kg •m/s = (3.5 kg) • v (0.5594 kg •m/s) / (3.5 kg) = v 0.1598 m/s = v

A 1.5-kg cannon is mounted on top of a 2.0-kg cart and loaded with a 52.7-gram ball. The cannon, cart, and ball are moving forward with a speed of 1.27 m/s. The cannon is ignited and launches a 52.7-gram ball forward with a speed of 75 m/s. Determine the post-explosion velocity of the cannon and cart.

a = v2 / R = (7.0 m/s)2 / (15.0 m) = 3.27 m/s/s Fnet = m • a = (55.0 kg) • (3.27 m/s/s) = 180 N Fgrav = Fvert = m • g = 539 N Fhoriz = Fnet = Ffrict = 180 N Theta = invtan(Fvert / Fhoriz) = invtan( 539 N / 180 N ) Theta = 71.6 degrees

A 55.0-kg softball player runs at 7.0 m/s around a curve whose radius is 15.0 m. The contact force (vector combination of the frictional force and the normal force) acting between the ground and the player's feet supply both the centripetal force for making the turn and the upward force for balancing the player's weight. Use a free-body diagram and your understanding of circular motion and Newton's second law to determine: a. acceleration b. Fgrav c. Fnorm d. Ffrict e. Angle of lean

Answer: 2.14 m/s (62.1 kg)(42.8 kg)(-3.11 m/s) =-133.11 kg*m/s then (62.1)(-133.11) (-133.11)/(62.1)=v = 2.14 m/s

A 62.1-kg male ice skater is facing a 42.8-kg female ice skater. They are at rest on the ice. They push off each other and move in opposite directions. The female skater moves backwards with a speed of 3.11 m/s. Determine the post-impulse speed of the male skater.

KE = 80 000 J The KE is directly related to the square of the speed. If the speed is reduced by a factor of 2 (as in from 60 mi/hr to 30 mi/hr) then the KE will be reduced by a factor of 4. Thus, the new KE is (320 000 J)/4 or 80 000 J.

A 900-kg compact car moving at 60 mi/hr has approximately 320 000 Joules of kinetic energy. Estimate its new kinetic energy if it is moving at 30 mi/hr. (HINT: use the kinetic energy equation as a "guide to thinking.")

The centripetal force on the Continental is four times greater than that of a Yugo. According to the equation Fnet=(m•v2) / R, force and mass are directly proportional. So 4 times the mass means 4 times the force.

A Lincoln Continental and a Yugo are making a turn. The Lincoln is four times more massive than the Yugo. If they make the turn at the same speed, then how do the centripetal forces acting upon the two cars compare. Explain.

Answer: 0.29 N Step 1: Identify known values in variable form. Q1 = -4.0 x 10^-6 C and Q2 = +4.0 x 10-6 C d = 0.70 m. Step 2: Identify requested information F = ??? Step 3: Substitute and solve. (See example B on the Tutorial page for sample algebra.)

A balloon with a charge of 4.0 µC is held a distance of 0.70 m from a second balloon having the same charge. Calculate the magnitude of the repulsive force.

A. p = 40 000 units (doubling the velocity will double the momentum) B. p = 60 000 units (tripling the velocity will triple the momentum) C. p = 40 000 units (doubling the mass will double the momentum) D. p = 80 000 units (doubling the velocity will double the momentum and doubling the mass will also double the momentum; the combined result is that the momentum is doubled twice -quadrupled)

A car possesses 20 000 units of momentum. What would be the car's new momentum if ... a. its velocity was doubled. b. its velocity was tripled. c. its mass was doubled (by adding more passengers and a greater load) d. both its velocity was doubled and its mass was doubled.

b. decrease the voltage of the battery (remove a cell) and D.increase the resistance of the circuit

A certain electrical circuit contains a battery with three cells, wires and a light bulb. Which of the following would cause the bulb to shine less brightly? Choose all that apply. a. increase the voltage of the battery (add another cell) b. decrease the voltage of the battery (remove a cell) c. decrease the resistance of the circuit d. increase the resistance of the circuit

both b. frequency & c. period

A child in a swing makes one complete back and forth motion in 3.2 seconds. This statement provides information about the child's a. speed b. frequency c. period

Without actually letting go of the ball, the clown will not be displaced from his original position. He may slide backwards a little and then forwards a little as he goes through the motion of the throwing the ball. But when he is done doing the motion, he will be at rest in his original position.

A clown is on the ice rink with a large medicine ball. If the clown throws the ball forward, then he is set into backwards motion with the same momentum as the ball's forward momentum. What would happen to the clown if he goes through the motion of throwing the ball without actually letting go of it? Explain.

(11 s) / (33 cycles) = 0.33 seconds.

A common physics lab involves the study of the oscillations of a pendulum. If a pendulum makes 33 complete back-and-forth cycles of vibration in 11 seconds, then its period is ______.

Answer: F

A conductor differs from an insulator in that a conductor ________. a. has an excess of protons b. has an excess of electrons c. can become charged and an insulator cannot d. has faster moving molecules e. does not have any neutrons to get in the way of electron flow f. none of these

d. electric charges move in a loop

A current is said to exist whenever _____. a. a wire is charged b. a battery is present c. electric charges are unbalanced d. electric charges move in a loop

a, b, c: the same for each. Both the Volkswagon and the large truck encounter the same force, the same impulse, and the same momentum change (for reasons discussed in this lesson). d: Acceleration is greatest for the Volkswagon. While the two vehicles experience the same force, the acceleration is greatest for the Volkswagon due to its smaller mass. If you find this hard to believe, then be sure to read the next question and its accompanying explanation.

A large truck and a Volkswagen have a head-on collision. a. Which vehicle experiences the greatest force of impact? b. Which vehicle experiences the greatest impulse? c. Which vehicle experiences the greatest momentum change? d. Which vehicle experiences the greatest acceleration?

c. able to interact

A medium is able to transport a wave from one location to another because the particles of the medium are ____. a. frictionless b. isolated from one another c. able to interact d. very light

Answer: BCD

A metal sphere is electrically neutral. It is touched by a positively charged metal rod. As a result, the metal sphere becomes charged positively. Which of the following occur during the process? List all that apply. a. The metal sphere gains some protons.,/p. b. Electrons are transferred from the sphere to the rod. c. The metal sphere loses electrons. d. The overall charge of the system is conserved. e. Protons are transferred from the rod to the sphere. f. Positive electrons are moved between the two objects.

Answer: B

A neutral metal sphere is touched by a negatively charged metal rod. As a result, the sphere will be ____ and the metal rod will be ____. Select the two answers in their respective order. a. positively charged b. negatively charged c. neutral d. much more massive e. ... not enough information to tell

Answer: C

A neutral metal sphere is touched by a negatively charged metal rod. During the process, electrons are transferred from the _____ to the _____ and the sphere acquires a _____ charge. a. neutral sphere, charged rod, negative b. neutral sphere, charged rod, positive c. charged rod, neutral sphere, negative d. charged rod, neutral sphere, positive e. ... nonsense! None of these describe what occurs.

Answer: E

A neutral metal sphere is touched by a positively charged metal rod. During the process, protons are transferred from the _____ to the _____ and the sphere acquires a _____ charge. a. charged rod, neutral sphere, negative b. charged rod, neutral sphere, positive c. neutral sphere, charged rod, negative d. neutral sphere, charged rod, positive e. ... nonsense! None of these describe what occurs.

A. 1/(5 s) = 0.20 Hz

A period of 5.0 seconds corresponds to a frequency of ________ Hertz. a. 0.2 b. 0.5 c. 0.02 d. 0.05 e. 0.002

Answer: F

A physics student, standing on the ground, touches an uncharged plastic baseball bat to a negatively charged electroscope. This will cause ___. a. the electroscope to be grounded as electrons flow out of the electroscope. b. the electroscope to be grounded as electrons flow into the electroscope. c. the electroscope to be grounded as protons flow out of the electroscope. d. the electroscope to be grounded as protons flow into the electroscope. e. the baseball bat to acquire an excess of protons. f. absolutely nothing (or very little) to happen since the plastic bat does not conduct.

Answers: B, D, G For A: protons are not transferred in electrostatics. For C: charge is neither created nor destroyed (ever). For E: electrons are simply transferred, consistent with the law of conservation of charge. For F: protons are not transferred in electrostatic experiments (the electrons are transferred). For H: If glass transfers electrons to felt, then the felt must be more electron-hungry.

A physics teacher rubs a glass object and a felt cloth together and the glass becomes positively charged. Which of the following statements are true? Circle all that apply. a. The glass gained protons during the rubbing process. b. The felt became charged negatively during this rubbing process. c. Charge is created during the rubbing process; it is grabbed by the more charge-hungry object. d. If the glass acquired a charge of +5 units, then the felt acquires a charge of -5 units. e. This event violates the law of conservation of charge. f. Electrons are transferred from glass to felt; protons are transferred from felt to glass. g. Once charged in this manner, the glass object and the felt cloth should attract each other. h. In general, glass materials must have a greater affinity for electrons than felt materials.

Answer: B

A positively charged pop can is touched by a person standing on the ground. The pop can subsequently becomes neutral. The pop can becomes neutral during this process because ______. a. electrons pass from the pop can to the person (ground) b. electrons pass from the person (ground) to the pop can c. protons pass from the pop can to the person (ground) d. protons pass from the person (ground) to the pop can

Answer: A

A rubber balloon possesses a positive charge. If brought near and touched to the door of a wooden cabinet, it sticks to the door. This does not occur with an uncharged balloon. These two observations can lead one to conclude that the wall is _____. a. electrically neutral b. negatively charged c. a conductor d. lacking electrons

Answer: f = 70 Hz and λ = 5.0 m The frequency is given and the wavelength is the v/f ratio.

A ruby-throated hummingbird beats its wings at a rate of about 70 wing beats per second. a. What is the frequency in Hertz of the sound wave? b. Assuming the sound wave moves with a velocity of 350 m/s, what is the wavelength of the wave?

This is an example of faulty physics in film. Sound is a mechanical wave and could never be transmitted through the vacuum of outer space.

A science fiction film depicts inhabitants of one spaceship (in outer space) hearing the sound of a nearby spaceship as it zooms past at high speeds. Critique the physics of this film.

d. a medium is required in order for sound waves to transport energy.

A sound wave is a mechanical wave, not an electromagnetic wave. This means that a. particles of the medium move perpendicular to the direction of energy transport. b. a sound wave transports its energy through a vacuum. c. particles of the medium regularly and repeatedly oscillate about their rest position. d. a medium is required in order for sound waves to transport energy.

The student weighs 784 N (Fgrav= 80 kg * 9.8 m/s/s). To lift a 784-Newton person at constant speed, 784 N of force must be applied to it (Newton's laws). The force is up, the displacement is up, and so the angle theta in the work equation is 0 degrees. Thus, W = (784 N) * (8 m) * cos (0 degrees) = 6272 Joules close

A student with a mass of 80.0 kg runs up three flights of stairs in 12.0 sec. The student has gone a vertical distance of 8.0 m. Determine the amount of work done by the student to elevate his body to this height. Assume that his speed is constant.

D. f =10 cycles / 120 s = 0.0833 cycles/s

A tennis coach paces back and forth along the sideline 10 times in 2 minutes. The frequency of her pacing is ________ Hz. a. 5.0 b. 0.20 c. 0.12 d. 0.083

d. both northward and southward

A transverse wave is transporting energy from east to west. The particles of the medium will move_____. a. east to west only b. both eastward and westward c. north to south only d. both northward and southward

The ball will move along a path which is tangent to the spiral at the point where it exits the tube. At that point, the ball will no longer curve or spiral, but rather travel in a straight line in the tangential direction.

A tube is been placed upon the table and shaped into a three-quarters circle. A golf ball is pushed into the tube at one end at high speed. The ball rolls through the tube and exits at the opposite end. Describe the path of the golf ball as it exits the tube.

1/(51.2 Hz) which is 0.0195 seconds.

A wave is introduced into a thin wire held tight at each end. It has an amplitude of 3.8 cm, a frequency of 51.2 Hz and a distance from a crest to the neighboring trough of 12.8 cm. Determine the period of such a wave.

d. longitudinal

A wave is transporting energy from left to right. The particles of the medium are moving back and forth in a leftward and rightward direction. This type of wave is known as a ____. a. mechanical b. electromagnetic c. transverse d. longitudinal

- 1.6 x 10-19 C. Answers: a. 0.132 C b. 0.00723 C (7.23 x 10-3 C) c. 3.83 C d. 0 Coulombs

After some rather exhausting counting (and a rather tall tale), a physics teacher determines that a very small sample of an object contains ... a. ... 8.25749 x 1017 protons and 5.26 x 1014 electrons; the charge on this object is ____ Coulombs. b. ... 3.12 x 1014 protons and 4.5488 x 1016 electrons; the charge on this object is ____ Coulombs. c. ... 2.40277 x 1019 protons and 9.88 x 1016 electrons; the charge on this object is ____ Coulombs. d. ... 2.6325 x 1015 protons and 2.6325 x 1015 electrons; the charge on this object is ____ Coulombs.

d = v • t = (340 m/s) • (0.075 s) = 25.5 m (0.150/2=0.075)

An automatic focus camera is able to focus on objects by use of an ultrasonic sound wave. The camera sends out sound waves that reflect off distant objects and return to the camera. A sensor detects the time it takes for the waves to return and then determines the distance an object is from the camera. The camera lens then focuses at that distance. Now that's a smart camera! In a subsequent life, you might have to be a camera; so try this problem for practice: If a sound wave (speed = 340 m/s) returns to the camera 0.150 seconds after leaving the camera, then how far away is the object?

c. quadrupled

An ocean wave has an amplitude of 2.5 m. Weather conditions suddenly change such that the wave has an amplitude of 5.0 m. The amount of energy transported by the wave is __________. a. halved b. doubled c. quadrupled d. remains the same

It will require more force to accelerate a full bucket of water compared to a half-full bucket. According to the equation Fnet = m•v2 / R, force and mass are directly proportional. So the greater the mass, the greater the force.

Anna Litical is practicing a centripetal force demonstration at home. She fills a bucket with water, ties it to a strong rope, and spins it in a circle. Anna spins the bucket when it is half-full of water and when it is quarter-full of water. In which case is more force required to spin the bucket in a circle? Explain using an equation as a "guide to thinking."

Fnorm = 1343 N, up Solution is as follows: First, draw a free-body diagram and note that Fgrav = 490 N, down. Second, calculate acceleration by a = v2 / R = (16 m/s)2 / (15 m) = 17.1 m/s/s, up Then note that Fnet = m • a = 853 N, up (toward center). Now Fgrav supplies 490 N of downward force, so the Fnorm must overcome this down force and still supply the sufficient Fnet in the up direction. Therefore, Fnorm = 1343 N,up.

Anna Litical is riding a "woody" roller coaster. Anna encounters the bottom of a small dip having a radius of curvature of 15.0 m. At the bottom of this dip Anna is traveling with a speed of 16.0 m/s and experiencing a much larger than usual normal force. Use Newton's second law to determine the normal force acting upon Anna's 50-kg body.

Fnorm = 135 N (top) and Fnorm = 1690 N (bottom) Use a, m, and g (9.8 m/s/s) with Fnet = m • a and Fgrav = m•g to find Fnet and Fgrav. Then use a free-body diagram to find Fnorm. Top: Fnet = 625 N, down and Fgrav = 490 N, down. So Fnorm = 135 N, down. Bottom: Fnet =1200 N, up and Fgrav = 490 N, So Fnorm =1690 N, up.

Anna Litical is riding on The Shock Wave at Great America. Anna experiences a downward acceleration of 12.5 m/s2 at the top of the loop and an upward acceleration of 24.0 m/s2 at the bottom of the loop. Use Newton's second law to determine the normal force acting upon Anna's 50-kg body at the top and at the bottom of the loop.

a. decreases

As the frequency of a wave increases, the period of the wave ___________. a. decreases b. increases c. remains the same

a. decrease

As the wavelength of a wave in a uniform medium increases, its frequency will _____. a. decrease b. increase c. remain the same

c. remain the same

As the wavelength of a wave in a uniform medium increases, its speed will _____. a. decrease b. increase c. remain the same

Answer: 0.030 m or 3.0 cm Step 1: Identify known values in variable form. Q1 = 1.0 x 10-6 C and Q2 = 1.0 x 10-6 C Felect = Fgrav = mg = 1.0 • 9.8 m/s/s = 9.8 N Step 2: Identify requested information d = ??? Step 3: Substitute and solve. (See example C on the Tutorial page for sample algebra.)

At what distance of separation must two 1.00-microCoulomb charges be positioned in order for the repulsive force between them to be equivalent to the weight (on Earth) of a 1.00-kg mass?

For the vertical part, W = (200 N) * (10 m) * cos (0 deg) = 2000 J. For the horizontal part, W = (50 N) * (35 m) * cos (0 deg) = 1750 J. The total work done is 3750 J (the sum of the two parts).

Ben Travlun carries a 200-N suitcase up three flights of stairs (a height of 10.0 m) and then pushes it with a horizontal force of 50.0 N at a constant speed of 0.5 m/s for a horizontal distance of 35.0 meters. How much work does Ben do on his suitcase during this entire motion?

The game will last two throws and one catch. When Chubby throws Flubby, the two will travel in opposite directions at the same speed. When Tubby catches Flubby, Flubby will slow down to half her original speed and move together with Tubby at that same speed. When Tubby throws Flubby towards Chubby, the greatest speed which Flubby can have is one-half the original speed. The game is now over since Flubby will never catch up to Chubby.

Chubby, Tubby and Flubby are astronauts on a spaceship. They each have the same mass and the same strength. Chubby and Tubby decide to play catch with Flubby, intending to throw her back and forth between them. Chubby throws Flubby to Tubby and the game begins. Describe the motion of Chubby, Tubby and Flubby as the game continues. If we assume that each throw involves the same amount of push, then how many throws will the game last?

When the slinky reaches the end of the slinky and hits Moe in the cheek, Moe expereinces a pulse of energy. The energy originated on Curly's end and is transported through the medium to Moe's end. The last particle on Moe's end transports that energy to Moe's cheek.

Curly and Moe are conducting a wave experiment using a slinky. Curly introduces a disturbance into the slinky by giving it a quick back and forth jerk. Moe places his cheek (facial) at the opposite end of the slinky. Using the terminology of this unit, describe what Moe experiences as the pulse reaches the other end of the slinky.

a. + charges move

Current has a direction. By convention, current is in the direction that ___. a. + charges move b. - electrons move c. + electrons move

a. the wavelength is halved and the speed remains constant

Dawn and Aram have stretched a slinky between them and begin experimenting with waves. As the frequency of the waves is doubled, a. the wavelength is halved and the speed remains constant b. the wavelength remains constant and the speed is doubled c. both the wavelength and the speed are halved. d. both the wavelength and the speed remain constant.

The fans will need to sway side to side. Thus, as the wave travels around the stadium they would be moving parallel to its direction of motion. If they rise up and sit down, then they would be creating a transverse wave.

Describe how the fans in a stadium must move in order to produce a longitudinal stadium wave.

Answer: Fnet = 533 N Given: m = 40 kg; R = 2.90 m; T = 2.93 s (since 10 cycles takes 29.3 s). First, find speed using speed=(2 • pi • R) / T = 6.22 m/s. Then find the acceleration using a = v2 / R = = (6.22 m/s)2 / (2.90 m) = 13.3 m/s/s Now use Fnet = m • a to find that Fnet = 533 N.

Determine the centripetal force acting upon a 40-kg child who makes 10 revolutions around the Cliffhanger in 29.3 seconds. The radius of the barrel is 2.90 meters.

Answer: 1.3 x 10-2 N, attractive (rounded from 1.296 x 10-2 N)

Determine the electrical force of attraction between two balloons that are charged with the opposite type of charge but the same quantity of charge. The charge on the balloons is 6.0 x 10-7 C and they are separated by a distance of 0.50 m.

Answer: 2.16 x 10-5 N, attractive

Determine the electrical force of attraction between two balloons with separate charges of +3.5 x 10-8 C and -2.9 x 10-8 C when separated a distance of 0.65 m

KE = 0.5*m*v2 KE = (0.5) * (625 kg) * (18.3 m/s)2 KE = 1.05 x105 Joules

Determine the kinetic energy of a 625-kg roller coaster car that is moving with a speed of 18.3 m/s.

Answer: +5.8 x 10^-7 Coulombs (rounded) To determine the charge on an object, determine the number of excess protons or excess electrons. Multiply the excess by the charge of an electron or the charge of a proton - 1.6 x 10-19 C. Finally, adjust the sign of the object to + or -.

Determine the quantity and type of charge on an object that has 3.62 x 1012 more protons than electrons.

Agree with Hector. A change in direction constitutes a velocity change and therefore an acceleration.

Dizzy Smith and Hector Vector are still discussing #1e. Dizzy says that the ball is not accelerating because its velocity is not changing. Hector says that since the ball has changed its direction, there is an acceleration. Who do you agree with? Argue a position by explaining the discrepancy in the other student's argumen

Answer: D

During a physics lab, a plastic strip was rubbed with cotton and became positively charged. The correct explanation for why the plastic strip becomes positively charged is that ... a. the plastic strip acquired extra protons from the cotton. b. the plastic strip acquired extra protons during the charging process. c. protons were created as the result of the charging process. d. the plastic strip lost electrons to the cotton during the charging process.

Answer: C Electric forces are repulsive for objects of like charge and attractive between objects of the opposite type of charge or between charged objects and neutral objects.

Electrical forces ____. a. can cause objects to only attract each other b. can cause objects to only repel each other c. can cause objects to attract or repel each other d. have no effect on objects

Trick Question! Each force is the same size. For every action, there is an equal ... (equal!). The fact that the firefly splatters only means that with its smaller mass, it is less able to withstand the larger acceleration resulting from the interaction. Besides, fireflies have guts and bug guts have a tendency to be splatterable. Windshields don't have guts. There you have it.

Express your understanding of Newton's third law by answering the following questions. Click the button to check your answers. 1. While driving down the road, a firefly strikes the windshield of a bus and makes a quite obvious mess in front of the face of the driver. This is a clear case of Newton's third law of motion. The firefly hit the bus and the bus hits the firefly. Which of the two forces is greater: the force on the firefly or the force on the bus?

*multiply all* A. p = m*v = 60 kg*9 m/s p = 540 kg•m/s, east B. p = m*v = 1000 kg*20 m/s p = 20 000 kg•m/s, north C. p = m*v = 40 kg*2 m/s p = 80 kg•m/s, south

Express your understanding of the concept and mathematics of momentum by answering the following questions. Click the button to view the answers. 1. Determine the momentum of a ... a. 60-kg halfback moving eastward at 9 m/s. b. 1000-kg car moving northward at 20 m/s. c. 40-kg freshman moving southward at 2 m/s.

Answer: D It is a common misconception that rockets are unable to accelerate in space. The fact is that rockets do accelerate. Rockets are able to accelerate due to the fact that they burn fuel and thrust the exhaust gases in a direction opposite the direction which they wish to accelerate.

For years, space travel was believed to be impossible because there was nothing that rockets could push off of in space in order to provide the propulsion necessary to accelerate. This inability of a rocket to provide propulsion in space is because ... a. space is void of air so the rockets have nothing to push off of. b. gravity is absent in space. c. space is void of air and so there is no air resistance in space. d. ... nonsense! Rockets do accelerate in space and have been able to do so for a long time.

T=1/(121 Hz) = 0.00826 s

Frieda the fly flaps its wings back and forth 121 times each second. The period of the wing flapping is ____ sec.

o lift a 15-Newton block at constant speed, 15-N of force must be applied to it (Newton's laws). Thus, W = (15 N) * (3 m) * cos (0 degrees) = 45 Joules

How much work is done by an applied force to lift a 15-Newton block 3.0 meters vertically at a constant speed?

The accelerator allows the car to increase speed. The brake pedal allows the car to decrease the speed. And the steering wheel allows the car to change direction.

Identify the three controls on an automobile that allow the car to be accelerated.

Since the ball has an upward momentum of 10 kg*m/s, the Earth must have a downward momentum of 10 kg*m/s. To find the velocity of the Earth, use the momentum equation, p = m*v. This equation rearranges to v=p/m. By substituting into this equation, v = (10 kg*m/s)/(6*1024 kg) v = 1.67*10-24 m/s (downward) Another way to write the velocity of the earth is to write it as 0.00000000000000000000000167 m/s

If a 5-kg bowling ball is projected upward with a velocity of 2.0 m/s, then what is the recoil velocity of the Earth (mass = 6.0 x 1024 kg).

The earth recoils with 10 units of momentum. This is not felt by Earth's occupants. Since the mass of the Earth is extremely large, the recoil velocity of the Earth is extremely small and therefore not felt.

If a ball is projected upward from the ground with ten units of momentum, what is the momentum of recoil of the Earth? ____________ Do we feel this? Explain.

b. do a lot of work on each charge it encounters

If a battery provides a high voltage, it can ____. a. do a lot of work over the course of its lifetime b. do a lot of work on each charge it encounters c. push a lot of charge through a circuit d. last a long time

W = F * d * cos Theta W = 14.7 N * 0.9 m * cos (0 degrees) W = 13.2 J (Note: The angle between F and d is 0 degrees because the F and d are in the same directionn)

If a force of 14.7 N is used to drag the loaded cart (from previous question) along the incline for a distance of 0.90 meters, then how much work is done on the loaded cart?

B. gallons of water flowing down slide per minute

If an electric circuit could be compared to a water circuit at a water park, then the current would be analogous to the ____. Choices: A. water pressure B. gallons of water flowing down slide per minute C. water D. bottom of the slide E. water pump F. top of the slide

d. the water pressure between the top and bottom of the circuit

If an electrical circuit were analogous to a water circuit at a water park, then the battery voltage would be comparable to _____. a. the rate at which water flows through the circuit b. the speed at which water flows through the circuit c. the distance that water flows through the circuit d. the water pressure between the top and bottom of the circuit e. the hindrance caused by obstacles in the path of the moving water

c. the pump that moves water from the ground to the elevated positions

If the electrical circuit in your Walkman were analogous to a water circuit at a water park, then the battery would be comparable to _____. a. the people that slide from the elevated positions to the ground b. the obstacles that stand in the path of the moving water c. the pump that moves water from the ground to the elevated positions d. the pipes through which water flows e. the distance that water flows through the circuit

a. one-third as much

If the resistance of a circuit were tripled, then the current through the circuit would be ____. a. one-third as much b. three times as much c. unchanged d. ... nonsense! There would be no way to make such a prediction.

If the speed is doubled, then the KE is quadrupled. Thus, KE = 4 * (1.04653 x 105 J) = 4.19 x 105 Joules. or KE = 0.5*m*v2 KE = 0.5*625 kg*(36.6 m/s)2 KE = 4.19 x 105 Joules

If the roller coaster car in the above problem were moving with twice the speed, then what would be its new kinetic energy?

b. four times as much

If the voltage across a circuit is quadrupled, then the current through the circuit would be ____. a. one-fourth as much b. four times as much c. unchanged d. ... nonsense! There would be no way to make such a prediction.

b. The particles vibrate vertically, perpendicular to the direction of the rod.

If you strike a horizontal rod vertically from above, what can be said about the waves created in the rod? a. The particles vibrate horizontally along the direction of the rod. b. The particles vibrate vertically, perpendicular to the direction of the rod. c. The particles vibrate in circles, perpendicular to the direction of the rod. d. The particles travel along the rod from the point of impact to its end.

Someone who doesn't know much physics. In such a situation as this, the target would be a safer place to stand than the rifle. The rifle would have a recoil velocity that is ten times larger than the bullet's velocity. This would produce the effect of "the rifle actually being the bullet."

In an effort to exact the most severe capital punishment upon a rather unpopular prisoner, the execution team at the Dark Ages Penitentiary search for a bullet that is ten times as massive as the rifle itself. What type of individual would want to fire a rifle that holds a bullet that is ten times more massive than the rifle? Explain.

Answer: B and C

In the above situation, the conducting sphere is ____. List all that apply. a. charged b. uncharged (neutral) c. polarized

Don't do this at home (at least, not if you wish to dock the boat)! As Kent jumps to reach the dock, the rowboat pushes Kent forward and thus Kent pushes the rowboat backwards. Kent will indeed reach the dock; but Kent's rowboat will be several feet away when he turns around to dock it. That makes it very difficult for Kent to dock the boat.

Kent Swimm, who is taking Physics for the third year in a row (and not because he likes it), has rowed his boat within three feet of the dock. Kent decides to jump onto the dock and turn around and dock his boat. Explain to Kent why this docking strategy is not a good strategy.

The point returns to its original position.

Mac and Tosh are experimenting with pulses on a rope. They vibrate an end up and down to create the pulse and observe it moving from end to end. How does the position of a point on the rope, before the pulse comes, compare to the position after the pulse has passed?

GIVEN: d (1-way) =25 m, t (2-way)=25 s Find v. If the pool is 25 meters long, then the back-and-forth distance is 50 meters. The wave covers this distance in 25 seconds. Now use v = d / t. v = d / t = (50 m) / (25 s) = 2 m/s

Mac and Tosh are resting on top of the water near the end of the pool when Mac creates a surface wave. The wave travels the length of the pool and back in 25 seconds. The pool is 25 meters long. Determine the speed of the wave.

Amplitude = 16 cm (Amplitude is the distance from the rest position to the crest position which is half the vertical distance from a trough to a crest.) Wavelength = 96 cm (Wavelength is the distance from crest to crest, which is twice the horizontal distance from crest to nearest trough.) Period = 0.42 s (The period is the reciprocal of the frequency. T = 1 / f)

Mac and Tosh stand 8 meters apart and demonstrate the motion of a transverse wave on a snakey. The wave can be described as having a vertical distance of 32 cm from a trough to a crest, a frequency of 2.4 Hz, and a horizontal distance of 48 cm from a crest to the nearest trough. Determine the amplitude, period, and wavelength of such a wave.

Answer: B The force on the rifle equals the force on the bullet. Yet, acceleration depends on both force and mass. The bullet has a greater acceleration due to the fact that it has a smaller mass. Remember: acceleration and mass are inversely proportional.

Many people are familiar with the fact that a rifle recoils when fired. This recoil is the result of action-reaction force pairs. A gunpowder explosion creates hot gases that expand outward allowing the rifle to push forward on the bullet. Consistent with Newton's third law of motion, the bullet pushes backwards upon the rifle. The acceleration of the recoiling rifle is ... a. greater than the acceleration of the bullet. b. smaller than the acceleration of the bullet. c. the same size as the acceleration of the bullet.

Ben Travlun is correct. The bug and bus experience the same force, the same impulse, and the same momentum change (as discussed in this lesson). This is contrary to the popular (though false) belief which resembles Miles' statement. The bug has less mass and therefore more acceleration; occupants of the very massive bus do not feel the extremely small acceleration. Furthermore, the bug is composed of a less hardy material and thus splatters all over the windshield. Yet the greater "splatterability" of the bug and the greater acceleration do not mean the bug has a greater force, impulse, or momentum change.

Miles Tugo and Ben Travlun are riding in a bus at highway speed on a nice summer day when an unlucky bug splatters onto the windshield. Miles and Ben begin discussing the physics of the situation. Miles suggests that the momentum change of the bug is much greater than that of the bus. After all, argues Miles, there was no noticeable change in the speed of the bus compared to the obvious change in the speed of the bug. Ben disagrees entirely, arguing that that both bug and bus encounter the same force, momentum change, and impulse. Who do you agree with? Support your answer.

Ocean waves do not transport water. An ocean wave could not bring a single drop of water from the middle of the ocean to shore. Ocean waves can only bring energy to the shore; the particles of the medium (water) simply oscillate about their fixed position. As such, water does not pile up on the beach.

Minute after minute, hour after hour, day after day, ocean waves continue to splash onto the shore. Explain why the beach is not completely submerged and why the middle of the ocean has not yet been depleted of its water supply.

KE = 0.5*m*v2 12 000 J = (0.5) * (40 kg) * v2 300 J = (0.5) * v2 600 J = v2 v = 24.5 m/s

Missy Diwater, the former platform diver for the Ringling Brother's Circus, had a kinetic energy of 12 000 J just prior to hitting the bucket of water. If Missy's mass is 40 kg, then what is her speed?

c. potential energy of

Moving an electron within an electric field would change the ____ the electron. a. mass of b. amount of charge on c. potential energy of

Fnorm = 116 N (top) and Fnorm = 2404 N (bottom) Use a, m, and g (9.8 m/s/s) with Fnet = m • a and Fgrav = m • g to find Fnet and Fgrav. Then use a free-body diagram to find Fnorm. Top: a = v2 / R = (6 m/s)2 / (3.2 m) = 11.25 m/s2 Fnet = 900 N, down and Fgrav = 784 N, down. So Fnorm = 116 N, down. Bottom: a = v2 / R = (18 m/s)2 / (16 m) = 20.25 m/s2 Fnet = 1620 N, up and Fgrav = 784 N, So Fnorm = 2404 N, up.

Noah Formula is riding a roller coaster and encounters a loop. Noah is traveling 6 m/s at the top of the loop and 18.0 m/s at the bottom of the loop. The top of the loop has a radius of curvature of 3.2 m and the bottom of the loop has a radius of curvature of 16.0 m. Use Newton's second law to determine the normal force acting upon Noah's 80-kg body at the top and at the bottom of the loop.

Fnorm = 523 N Solution is as follows: First, draw a free-body diagram and note that Fgrav = 784 N, down. Second, calculate acceleration by a = v2 / R = (14 m/s)2 / (12 m) = 16.3 m/s/s. Then note that Fnet = m • a = 1307 N down (toward center). Now Fgrav supplies 784 N of this downward force, so the Fnorm must supply the rest. Therefore, Fnorm = 523 N.

Noah Formula is riding an old-fashioned roller coaster. Noah encounters a small hill having a radius of curvature of 12.0 m. At the crest of the hill, Noah is lifted off his seat and held in the car by the safety bar. If Noah is traveling with a speed of 14.0 m/s, then use Newton's second law to determine the force applied by the safety bar upon Noah's 80-kg body.

A. f = 1 cycle / (60 s) = (1 / 60) Hz

Non-digital clocks (which are becoming more rare) have a second hand that rotates around in a regular and repeating fashion. The frequency of rotation of a second hand on a clock is _______ Hz. a. 1/60 b. 1/12 c. 1/2 d. 1 e. 60

The wavelength is 8.6 meters and the period is 6.2 seconds. The frequency can be determined from the period. If T = 6.2 s, then f =1 /T = 1 / (6.2 s) f = 0.161 Hz Now find speed using the v = f • λ equation. v = f • λ = (0.161 Hz) • (8.6 m) v = 1.4 m/s

Ocean waves are observed to travel along the water surface during a developing storm. A Coast Guard weather station observes that there is a vertical distance from high point to low point of 4.6 meters and a horizontal distance of 8.6 meters between adjacent crests. The waves splash into the station once every 6.2 seconds. Determine the frequency and the speed of these waves.

A. 1 cycles/2 s = 0.5 Hz.

Olive Udadi accompanies her father to the park for an afternoon of fun. While there, she hops on the swing and begins a motion characterized by a complete back-and-forth cycle every 2 seconds. The frequency of swing is _________. a. 0.5 Hz b. 1 Hz c. 2 Hz

"I'll bet you 20 bucks you're wrong." or "No Way!" or ... Electrons are not positively charged. Positively charged objects have an excess of protons (which are positively charged).

Respond to the following student statement: "A positively charged object is an object that has an excess of positive electrons."

Answer: Saran Wrap

Saran Wrap has a larger electron affinity than Nylon. If Nylon is rubbed against Saran Wrap, which would end up with the excess negative charge? ____________ Explain.

Answer: C

Suppose that a conducting sphere is charged positively by some method. The charge is initially deposited on the left side of the sphere. Yet because the object is conductive, the charge spreads uniformly throughout the surface of the sphere. The uniform distribution of charge is explained by the fact that ____. a. the charged atoms at the location of charge move throughout the surface of the sphere b. the excess protons move from the location of charge to the rest of the sphere c. excess electrons from the rest of the sphere are attracted towards the excess protons

FALSE! The speed of a wave is unaffected by changes in the frequency.

T OR F.............Doubling the frequency of a wave source doubles the speed of the waves.

Answer: False

TRUE or FALSE: An object that becomes grounded gains neutrons during the grounding process.

FALSE

TRUE or FALSE: In order for John to hear Jill, air molecules must move from the lips of Jill to the ears of John.

Answer: False Electrically neutral atoms simply possess the same number of electrons as protons. This gives the objects a balance of both type of charge.

TRUE or FALSE: An object that is electrically neutral contains only neutrons.

Answer: False Negatively charged objects have protons; it's just their number of electrons is greater than their number of protons.

TRUE or FALSE: An object that is negatively charged could contain only electrons with no accompanying protons.

Answer: False Positively charged objects have electrons; they simply possess more protons than electrons.

TRUE or FALSE: An object that is positively charged contains all protons and no electrons.

Doubling the speed of the ride will cause the force to be four times greater than the original force. According to the equation Fnet=(m•v2) / R, force and speed2 are directly proportional. So 2X the speed means 4X the force (that's from 22).

The Cajun Cliffhanger at Great America is a ride in which occupants line the perimeter of a cylinder and spin in a circle at a high rate of turning. When the cylinder begins spinning very rapidly, the floor is removed from under the riders' feet. What affect does a doubling in speed have upon the centripetal force? Explain.

Answer: 6.25 x 1019 electrons Multiply the charge in Coulombs (10 C) by the conversion factor: (1 electron) / (1.6 x 10-19 C). The units of C cancel; the answer is in electrons.

The amount of charge carried by a lightning bolt is estimated at 10 Coulombs. What quantity of excess electrons is carried by the lightning bolt?

d. very slow; slower than a snail

The drift velocity of mobile charge carriers in electric circuits is ____. a. very fast; less than but very close to the speed of light b. fast; faster than the fastest car but nowhere near the speed of light c. slow; slower than Michael Jackson runs the 220-meters d. very slow; slower than a snail

T = 1 / f = 1 / (440 HZ) = 0.00227 s

The period of the sound wave produced by a 440 Hertz tuning fork is ___________.

potential energy per charge

The quantity electric potential is defined as the amount of _____. a. electric potential energy b. force acting upon a charge c. potential energy per charge d. force per charge

Longitudinal

The sonar device on a fishing boat uses underwater sound to locate fish. Would you expect sonar to be a longitudinal or a transverse wave?

a. the properties of the medium through which the wave travels

The speed of a wave depends upon (i.e., is causally affected by) ... a. the properties of the medium through which the wave travels b. the wavelength of the wave. c. the frequency of the wave. d. both the wavelength and the frequency of the wave.

Answer: False

True or False: When an object becomes polarized, it acquires a charge and becomes a charged object.

Answer: 0.080 N Explanation: The electrostatic force is directly related to the product of the charges and inversely related to the square of the separation distance. Doubling both of the charges would serve to quadruple the force. Doubling the distance would serve to reduce the force by a factor of four. The combined affect of these two variations would be to not change the force at all; it remains as 0.080 N.

Two charged objects have a repulsive force of 0.080 N. If the charge of both of the objects is doubled and the distance separating the objects is doubled, then what is the new force?

Answer: 0.320 N Explanation: Electrostatic force is directly related to the charge of each object. So if the charge of both objects is doubled, then the force will become four times greater. Four times 0.080 N is 0.320 N.

Two charged objects have a repulsive force of 0.080 N. If the charge of both of the objects is doubled, then what is the new force?

Answer: 0.040 N Explanation: The electrostatic force is directly related to the product of the charges and inversely related to the square of the separation distance. Doubling one of the charges would serve to double the force. Doubling the distance would serve to reduce the force by a factor of four. The combined affect of these two variations would be to decrease the force by a factor of two - changing it from 0.080 N to 0.040 N.

Two charged objects have a repulsive force of 0.080 N. If the charge of one of the objects is doubled, and the distance separating the objects is doubled, then what is the new force?

Answer: 0.160 N Explanation: Electrostatic force is directly related to the charge of each object. So if the charge of one object is doubled, then the force will become two times greater. Two times 0.080 N is 0.160 N.

Two charged objects have a repulsive force of 0.080 N. If the charge of one of the objects is doubled, then what is the new force?

Answer: 0.020 N Explanation: The electrostatic force is inversely related to the square of the separation distance. So if d is two times larger, then F is four times smaller - that is, one-fourth the original value. One-fourth of 0.080 N is 0.020 N.

Two charged objects have a repulsive force of 0.080 N. If the distance separating the objects is doubled, then what is the new force?

Answer: 0.320 N Explanation: The electrostatic force is inversely related to the square of the separation distance. So if d is two times smaller, then F is four times larger. Four times 0.080 N is 0.320 N

Two charged objects have a repulsive force of 0.080 N. If the distance separating the objects is halved, then what is the new force?

Answer: 0.00889 N Explanation: The electrostatic force is inversely related to the square of the separation distance. So if d is three times larger, then F is nine times smaller - that is, one-ninth the original value. One-ninth of 0.080 N is 0.00889 N.

Two charged objects have a repulsive force of 0.080 N. If the distance separating the objects is tripled, then what is the new force?

Answer: 0.080 N Explanation: The electrostatic force is directly related to the product of the charges and inversely related to the square of the separation distance. Quadrupling one of the charges would serve to quadruple the force. Doubling the distance would serve to reduce the force by a factor of four. The combined affect of these two variations would be to not alter the force at all; it would remain as 0.080 N.

Two charged objects have an attractive force of 0.080 N. If the charge of one of the objects is increased by a factor of four, and the distance separating the objects is doubled, then what is the new force?

Answer: 0.0267 N Explanation: The electrostatic force is directly related to the product of the charges and inversely related to the square of the separation distance. Tripling one of the charges would serve to triple the force. Tripling the distance would serve to reduce the force by a factor of nine. The combined affect of these two variations would be to make the force 3/9-ths or 1/3-rd the original value. One-third of 0.080 N is 0.0267 N.

Two charged objects have an attractive force of 0.080 N. If the charge of one of the objects is tripled and the distance separating the objects is tripled, then what is the new force?

Answer: 0.0050 N Explanation: The electrostatic force is inversely related to the square of the separation distance. So if d is four times larger (quadrupled), then F is 16 times smaller - that is, 1/16-th the original value. One-sixteenth of 0.080 N is 0.0050 N.

Two charged objects have an attractive force of 0.080 N. If the distance separating the objects is quadrupled, then what is the new force?

Answer: C In this situation, the force on the first ice dancer is the same as the force on the second ice dancer (Newton's third law of motion). And these forces act for the same amount of time to cause equal impulses on each skater. Since impulse is equal to momentum change, both skaters must also have equal momentum changes. The mass of the individual skaters will only effect the subsequent velocity change.

Two ice dancers are at rest on the ice, facing each other with their hands together. They push off on each other in order to set each other in motion. The subsequent momentum change (magnitude only) of the two skaters will be ____. a. greatest for the skater who is pushed upon with the greatest force b. greatest for the skater who pushes with the greatest force c. the same for each skater d. greatest for the skater with the most mass e. greatest for the skater with the least mass

Answer: E Before the explosion, the cans were at rest. Thus, the pre-explosion momentum of the system was 0. If the system can be considered isolated (as stated), then the post-explosion momentum must also be 0.

Two pop cans are at rest on a stand. A firecracker is placed between the cans and lit. The firecracker explodes and exerts equal and opposite forces on the two cans. Assuming the system of two cans to be isolated, the post-explosion momentum of the system ____. a. is dependent upon the mass and velocities of the two cans b. is dependent upon the velocities of the two cans (but not their mass) c. is typically a very large value d. can be a positive, negative or zero value e. is definitely zero

d. four times larger than

Two waves are traveling through a container of an inert gas. Wave A has an amplitude of 0.1 cm. Wave B has an amplitude of 0.2 cm. The energy transported by wave B must be __________ the energy transported by wave A. a. one-fourth b. one-half c. two times larger than d. four times larger than

c. the same as

Two waves are traveling through the same container of nitrogen gas. Wave A has a wavelength of 1.5 m. Wave B has a wavelength of 4.5 m. The speed of wave B must be ________ the speed of wave A. a. one-ninth b. one-third c. the same as d. three times larger than

b. 1:2

Two waves on identical strings have frequencies in a ratio of 2 to 1. If their wave speeds are the same, then how do their wavelengths compare? a. 2:1 b. 1:2 c. 4:1 d. 1:4

Answer: E Electrons are negatively charged and protons are positively charged. The neutrons do not have a charge.

Use your understanding of charge to answer the following questions. When finished, click the button to view the answers. 1. ____ are the charged parts of an atom. a. Only electrons b. Only protons c. Neutrons only d. Electrons and neutrons e. Electrons and protons f. Protons and neutrons

As fuel is pumped from the tanker car to a reservoir, charge can quickly build up as the fluid flows through the hoses. This static charge can create sparks capable of igniting the fuel. By connecting the body of the tanker car to the ground, the static charge can be transferred to the ground. A metal wire is used since metals are conductive and allow charge to flow through them.

When an oil tanker car has arrived at its destination, it prepares to empty its fuel into a reservoir or tank. Part of the preparation involves connecting the body of the tanker car with a metal wire to the ground. Suggest a reason for why is this done.

The hose is pushing lots of water (large mass) forward at a high speed. This means the water has a large forward momentum. In turn, the hose must have an equally large backwards momentum, making it difficult for the firefighters to manage.

When fighting fires, a firefighter must use great caution to hold a hose that emits large amounts of water at high speeds. Why would such a task be difficult?

increases and increases

When work is done on a positive test charge by an external force to move it from one location to another, potential energy _________ (increases, decreases) and electric potential _________ (increases, decreases).

c. They travel in a direction that is at right angles to the direction of the particles of the medium.

Which of the following is not a characteristic of mechanical waves? a. They consist of disturbances or oscillations of a medium. b. They transport energy. c. They travel in a direction that is at right angles to the direction of the particles of the medium. d. They are created by a vibrating source.

e. The battery supplies energy that raises charge from low to high voltage.

Which of the following is true about the electrical circuit in your flashlight? a. Charge moves around the circuit very fast - nearly as fast as the speed of light. b. The battery supplies the charge (electrons) that moves through the wires. c. The battery supplies the charge (protons) that moves through the wires. d. The charge becomes used up as it passes through the light bulb. e. The battery supplies energy that raises charge from low to high voltage. f. ... nonsense! None of these are true.

Answer; B, C and E Aluminum and silver are metals, making them good conductors. The human body is a fairly good conductor. When wet, its an even better conductor.

Which of the following materials are likely to exhibit more conductive properties than insulating properties? _____ Explain your answers. a. rubber b. aluminum c. silver d. plastic e. wet skin

both A. decrease the voltage and D. increase the resistance

Which of the following will cause the current through an electrical circuit to decrease? Choose all that apply. a. decrease the voltage b. decrease the resistance c. increase the voltage d. increase the resistance

Answer: C

Which statement best explains why a rubber rod becomes negatively charged when rubbed with fur? a. The rubber that the rod is made of is a better insulator than fur. b. The fur is a better insulator than the rubber. c. Molecules in the rubber rod have a stronger attraction for electrons than the molecules in the fur. d. Molecules in the fur have a stronger attraction for electrons than the molecules in the rubber rod.

GIVEN: v = 342 m/s, t = 0.82 s (2-way) Find d (1-way) If it takes 0.82 s to travel to the canyon wall and back (a down-and-back time), then it takes 0.41 s to travel the one-way distance to the wall. Now use d = v • t d = v • t = (342 m/s) • (0.41 s) = 140 m

While hiking through a canyon, Noah Formula lets out a scream. An echo (reflection of the scream off a nearby canyon wall) is heard 0.82 seconds after the scream. The speed of the sound wave in air is 342 m/s. Calculate the distance from Noah to the nearby canyon wall.

a = v2 / R = (27.0 m/s)2 / (1.25 m) = 583 m/s/s Fnet = m • a = (7.30 kg) • (583 m/s/s) = 4257 N Fgrav = Fvert = m • g = 71.5 N Fhoriz = Fnet = 4257 N Ftens = SQRT(Fvert2 + Fhoriz2) Ftens = 4258 N

n the hammer throw, a sphere is whirled around in a circular path on the end of a chain. After revolving about five times the thrower releases his grip on the chain and the "hammer" is launched at an angle to the horizontal. A diagram of the athlete and the hammer is shown to the right. Assume that the hammer is moving in a circle in a horizontal plane with a speed of 27.0 m/s. Assume that the hammer has a mass of 7.30-kg and that it moves in a circle with a 1.25-m radius. Since the hammer is moving in a horizontal plane, the centripetal force is directed horizontally. The vertical component of the tension in the chain (directed upward) is balanced by the weight of the hammer (directed downward). Use the diagram and an understanding of vector components to determine the tension in the chain.

Answer: 0.144 N Step 1: Identify known values in variable form. Q1 = -1.0 x 10^-6 C and Q2 = +4.0 x 10-6 C d = 50.0 cm = 0.50 m. Step 2: Identify requested information F = ??? Step 3: Substitute and solve. (See example B on the Tutorial page for sample algebra.)

oann has rubbed a balloon with wool to give it a charge of -1.0 x 10-6 C. She then acquires a plastic golf tube with a charge of +4.0 x 10-6 C localized at a given position. She holds the location of charge on the plastic golf tube a distance of 50.0 cm above the balloon. Determine the electrical force of attraction between the golf tube and the balloon.