Physics, Unit 1 and 2

1.0090 cm + 0.02 cm = cm

1.03

impulse

F △ t

mass

that which causes an object to have inertia

3.2 km is the same as 3.2 x 106 cm.

False

Newton's Second Law

F = ma

30,000 m is the same as 30 km.

True

Which of the following measurements is a scalar?

136 MB

When a car is 200 meters from its starting position traveling at 30. m/s., it starts braking and comes to a stop 350 meters from its starting position in 10. s. Calculate the acceleration. _____ m/s2

-3.0

A penny falls from a windowsill which is 25.0 m above the sidewalk. How much time does a passerby on the sidewalk below have to move out of the way before the penny hits the ground?

2.26

A penny falls from a windowsill 25.0 m above the sidewalk. How fast is the penny moving when it strikes the ground? (Remember that the velocity will be negative due to the downward motion of the penny)

-22.1

600,000 cm = km

6

2 g = mg

2,000

A caterpillar tries to climb straight up a wall a meter high, but for every 2 cm. up it climbs, it slides down 1 cm. Eventually, it reaches the top. When it reaches the top, it does not pull itself over so it will slide down 1 cm. At this point, the caterpillar was exhausted and fell to the ground. What is the total displacement?

0

Light travels 300,000,000 m/s, and one year has approximately 32,000,000 seconds. A light year is the distance light travels in one year. Calculate the distance in meters of one light year.

1 x 1016 m

Light travels 300,000,000 m/s, and one year has approximately 32,000,000 seconds. A light year is the distance light travels in one year. State this distance in centimeters.

1 x 1018 cm

If a cart of 2 kg mass has a force of 8 newtons exerted on it, what is its acceleration?

4

A 2,000-kg test car, traveling 60 m/s hits a brick wall. Using motion pictures, the time involved is determined to be 0.050 s. What impulse does the car impart to the wall?

1.2 x 10^5

Multiply 0.00032 cm by 4.02 cm and express the answer in scientific notation. Remember to follow significant figure rules.

1.3 -3

Calculate (4.2 ∙ 105) cm ∙ (4.0 ∙ 10-9) cm2.

1.7 -3

A car travels 30.0 km to the south and then turns around and travels 20.0 km to the north in 1.5 hours time. What is the car's total displacement? What is the car's average velocity?

10.0 6.7

A car travels 6 miles north, 3 miles east, and then 2 miles south. What is the distance traveled?

11

The impulse given to a ball with mass of 2.0 kg is 16 N*s. If the ball were already moving at 3.0 m/s., what would the final velocity be? (Remember that v = Vfinal - Vinitial )

11 m/s

Divide 0.0081 meters by 300 seconds and express the answer in scientific notation.

2.7 -5

Light travels 300,000,000 m/s, and one year has approximately 32,000,000 seconds. A light year is the distance light travels in one year. State the number of seconds in one year, using scientific notation.

3.2 x 107 s

An American Red Cross plane needs to drop emergency supplies to victims of a hurricane in a remote part of the world. The plane is traveling horizontally at 100.0 m/s at a height of 50.0 m above the ground. What horizontal distance does the package travel before striking the ground?

319

A 2.0-kg object moves in a circle of 0.50 m radius at 3.0 m/s. Calculate the centripetal force.

36N

A rocket sled is tested at "5 g" (5 times the acceleration due to gravity). If the sled starts from rest at position do= 0.00, how long does it take to travel 441 meters?

4.24

A penny is dropped into a well. It takes 5 seconds to fall. Calculate the depth of the well in feet.

400

A caterpillar tries to climb straight up a wall a meter high, but for every 2 cm up it climbs, it slides down 1 cm. Eventually, it reaches the top. When it reaches the top, it does not pull itself over so it will slide down 1 cm. What is the total displacement traveled? (Include direction, whether up, down, or n/a.)

99 up

The speedometer of the car shows that the average speed of the car is 55 mi/h.

False

Kepler discovered the forces that govern planetary motion.

False

Velocity is displacement divided by time, v = d/t. Given this, what is the basic SI units for velocity?

m/s

You have learned of two fundamental units that are not vector quantities. Which are they?

mass time

Assume a comet is traveling at a constant velocity in deep space. Why would it speed up as it approaches our solar system?

The gravitational force fields of the sun and planets in the solar system accelerates it.

If an object were released in space far away from planets or stars and given an initial momentum (mv), describe what would happen to that object.

The object in motion will stay in motion if there are no other forces affecting it.

A resultant occurs by combining two or more vectors, and a component occurs when a vector is split into its horizontal and vertical vectors.

True

While driving down the road, a grasshopper strikes the windshield of a bus and makes a mess in front of the face of the driver. This is a good example of Newton's third law of motion. The action is the grasshopper hitting the windshield and the reaction is the windshield stopping the grasshopper. Which of the two forces is greater: the force on the grasshopper or the force on the windshield?

both forces are the same

Select three different examples of accelerated motion.

a body traveling in a straight line and increasing in speed a body traveling in a straight line and decreasing in speed a body traveling at a constant speed and changing direction

centripetal acceleration

center-seeking change in direction of velocity

rotational speed

revolutions per minute (RPM)

Newton's Second Law

the acceleration of a mass directly proportional to the force acting on it

A batter swings at a baseball. The action force is the bat hitting the ball with a force of 5N. What is the reaction force?

the ball hitting the bat

A 230 kg steel crate is being pushed along a cement floor. The force of friction is 480 N to the left and the applied force is 1860 N to the right. The forces acting on the crate are _______

unbalanced

35 m is equivalent to how many km?

0.035 km

0.001s = ms

1

Your friend is 1.56 m tall. How many millimeters tall is your friend? mm

1,560

An object is dropped onto the moon (gm = 5 ft/s2). How long does it take to fall from an elevation of 250 ft.?

10

If a 1.50 kg mass revolves at the end of a string 0.50 m long, and its tangential speed is 6.0 m/s, calculate the centripetal force.

110

A force of 6N is exerted on a cart that is carrying a rock and produces an acceleration of 2 m/s2. If the cart has a mass of 1 kg, what is the mass of the rock?

2

A 2,000-kg test car, traveling 60 m/s hits a brick wall. Using motion pictures, the time involved is determined to be 0.050 s. What is the magnitude of the force that the car exerts on the wall?

2.4 x 10^6

An object on earth has a mass of 4 kg. Calculate its weight on another planet that has an acceleration due to gravity one-half that of the earth.

20

2 m is equivalent to how many mm (millimeters)?

2000 mm

A 1000-kg car traveling at 66 m/s hits a 2000-kg car at rest and the two travel together after the collision. Calculate the speed with which they move.

22 m/s

An object weighs 60.0 kg on the surface of the earth. How much does it weigh 4R from the surface? (5R from the center)

23.5N

acceleration due to gravity

32 ft/s2

An object moves in uniform circular motion at 25 m/s and takes 1.0 second to go a quarter circle. Calculate the centripetal acceleration.

39

43.278 kg - 28.1 g = kg

43.250

How many significant digits are in the measurement 50.003010 nm?

8

The impulse given to a ball with mass of 2 kg is 16 N*s. If the ball starts from rest, what is its final velocity?

8

Objects on the moon's surface have an acceleration due to gravity one-sixth that on the earth's. What would the 50.0 kg boy weigh on the moon?

81.7

If a fly sits halfway between the axis and the edge of a rotating phonograph turntable, what happens to its tangential speed when the RPM is tripled?

It triples.

If for every action force an equal and opposite reaction force exists, how can anything ever be accelerated?

The action and reaction forces act on different objects, therefore the net force is not always zero.

In comparing the Ptolemaic system to the Copernican system, neither is entirely correct since Ptolemy said the earth was at the center and Copernicus said the planets had circular orbits.

True

Newton's Second Law of Motion

acceleration is directly proportional to the force and inversely proportional to the mass

The weight of an apple at 4R from earth is ____ of that on earth.

one sixteenth

A car going 72.0 km/h (20.0 m/s) slows down to 36.0 km/h (10.0 m/s) in 5.00 seconds. Calculate the acceleration in m/s2.

-2.00

A train starts from rest and travels for 5.0 s with a uniform acceleration of 1.5 m/s 2. How far does the train travel in this time interval?

19

A mountain climber hikes 25.5 km from her base camp, going 20.0º north of east. On the second day, she walks 41.0 km in a direction 65.0º north of east, at which point she has reached a summit. Determine the magnitude and direction of her resultant displacement between the base camp and the second camp. (Remember to analyze the two motions separately, and then add and use Pythagorean theorem for the resultant and trigonometry for the angle.)

42º north of east

Calculate the force at sea level that a boy of mass 50 kg exerts on a chair in which he is sitting.

490

An object is dropped from a platform100 ft high. Ignoring wind resistance, what will its speed be when it reaches the ground?

80.0 ft/s

If an object starting from rest and position do = 0 attains a velocity of 20 m/s at d = 50 m, calculate the acceleration required.

4 m/s2

If, in the above diagram, no gravitational force retarded the ball's movement (that is, if the right hand side of the diagram were horizontal), how far would the ball travel?

indefinite distance

tangential speed

instantaneous linear speed of an object in circular motion

A 20.0kg cart travels at 10.0 m/s in a circle with a radius of 15.0 m. What is the centripetal force?

133 N

If a cart of 4 kg mass has a force of 8 newtons exerted on it, what is its acceleration?

2

"For every action there is an equal and opposite reaction", this statement is

Newton's Third Law

A 6000 kg train car traveling at 2.5 m/s collides with another 6000 kg train car, now they are both moving but with a speed of 1.25 m/s. This is an example of

The Law Of Conservation of Momentum

Newton's First Law

a special case of Galileo's Law of Inertia

Indicate the reasons why the centripetal acceleration (and centripetal force) always point to the center in uniform circular motion. Select all that apply.

a= v/t, and the v points toward the center of the circle. F=ma, and since "a" points toward the center, so does F.

Newton's First Law

an object in motion stays in motion unless an external force acts on it

Why does the momentum before a collision equal the momentum after a collision?

because momentum is conserved

impulse

force multiplied by time

centripetal force

force that produces uniform circular motion

An impulse always produces a change in

momentum

The feeling of weightlessness occurs because _____________________.

there is no supporting force under your mass.

momentum

velocity multiplied by mass

Express answer to nearest tenth. ∙ 10 m/day.

2.0 -9

If a car travels 30 mi. north for one-half hour, 50 mi. east for one hour, and 30 mi. south for 30 min., what is the total displacement of the car?

50 E

A train starts from rest and travels for 5.0 s with a uniform acceleration of 1.5 m/s2. What is the final velocity of the train?

7.5

If light intensity obeyed an inverse square law, you would expect to find the intensity to decrease as the inverse square of the distance.

True

A rifle is fired and recoils when the bullet leaves the gun. This is an example of Newton's third law. The acceleration of the bullet is

greater than that of the rifle

A missile is fired from a jet flying horizontally at Mach 1 (1100 ft/s). The missile has a horizontal acceleration of 1000 ft/s2. Calculate its horizontal velocity at 10.0 seconds after it is fired. (Assume constant acceleration of the missile throughout its flight.)

11,100 ft/s

An object is dropped from a platform100 ft high. Ignoring wind resistance, how long will it take to reach the ground?

2.5 s

2 km = cm

200,000

Find the force a 68.5 kg person would experience while standing on the surface of Mars. Mars has a mass of 6.43 x 1023 kg and a radius of 3.43 x 106m from its center to the surface.

250 N

A train goes up a hill with a 15º incline. If the train has constant speed of 22 m/s, what are the vertical and horizontal components of the train's velocity? (Remember to use the law of sine and cosines for this problem)

5.7 21

A force is exerted on a 4.0-kg mass producing an acceleration of 3.0 m/s2. If the mass were changed to 2 kg, the same force would produce how much acceleration on the object?

6

How many significant digits are in the measurement 4,032,010 m/s?

6

Divide 300 g2 by 0.0005 g and express the answer in scientific notation. Remember to follow significant figure rules.

6 5

If the 78.0 kg astronaut were in a spacecraft 6R from the center of the earth, what would the astronaut's weight be on earth? ___ in the spacecraft? ___

760N 21N

If in 30 minutes Allex runs to a store that is 4 km away, what is her average speed in km/h?

8

If a boy (m = 50kg) at rest on skates is pushed by another boy who exerts a force of 200 N on him and if the first boy's final velocity is 8 m/s, what was the contact time?

2

Do two objects (two large hunks of lead suspended from two strong strings) exert a gravitational force on each other?

yes

Calculate the velocity of a 1650 kg satellite that is in a circular orbit of 4.2 x 106m above the surface of a planet, which has a radius 3.95 x 105 m and the period of the orbit is 2.0 hours.

1.4 x 10^7m/h

If an object is thrown in an upward direction from the top of a building 160 ft. high at an initial speed of 21.82 mi/h., what is its final speed when it hits the ground?(Disregard wind resistance. Round answer according to significant figures and do not reflect negative direction in your answer.

110

Calculate the period (T) of uniform circular motion if the velocity is 40.0 m/s and centripetal acceleration is 20.0 m/s2.

12.6 s

Find the centripetal force needed by a 1275 kg car to make a turn of radius 40.0 m at a speed of 25.0 km/h.

1540 N

A magnetic hockey puck (0.40 kg) hits another hockey puck (0.40 kg) at rest and both travel together to the right at 8.0 m/s. How fast was the first hockey puck initially moving?

16

An object moves in uniform circular motion at 25 m/s and takes 1.0 second to go a quarter circle. What is the radius of the circle?

16 m

A 230 kg steel crate is being pushed along a cement floor. The force of friction is 480 N to the left and the applied force is 1860 N to the right. What is the normal force?

2300 N up

If an object moves in uniform circular motion in a circle of radius R = 1.00 meter, and the object takes 4.00 seconds to complete ten revolutions, calculate the centripetal acceleration.

247 m/s2

Express 50,000 m/s2 in scientific notation.

5.0 x 104m/s2

A 230 kg steel crate is being pushed along a cement floor. The force of friction is 480 N to the left and the applied force is 1860 N to the right. What is the acceleration of the crate? (Hint: remember to find net force first)

6.0

Express 0.00000000062 kg in scientific notation.

6.2 x 10-10kg

If a racket strikes a ball (m = 100 g) with a force of 2000 N for 0.3 s., calculate the velocity the ball has as it leaves the racket, assuming it starts from rest.

6000 m/s

The earth takes 1 year to revolve around the sun at 1 A.U. distance (an astronomical unit = 93,000,000 miles). If a planet were 4 A.U. from the sun, how many years would it take to make 1 orbit?

8

When a car screeches to a sudden stop to avoid hitting a dog, it slows down from 9.00 m/s to 0.00 m/s in 1.50 s. Find the average acceleration of the car.

-6.00

What is the vector sum of 5 km east and 5 km west?

0

You travel 20.0 mph for 0.500 hour, 40.0 mph for 1.00 hour, 30.0 mph for 0.500 hour, and 50.0 mph for 2.00 hours. What is the total distance traveled?

165 miles

A skier descends a mountain at an angle of 35.0º to the horizontal. If the mountain is 235 m long, what are the horizontal and vertical components of the skier's displacement? (Use trigonometry to solve.)

193 m 135 m

Calculate the distance in km that Allex can run in 2 hours if she maintains the constant average speed of 8 km/h.

20 km

You hit a golf ball 30.0 m to the south and overshoot the hole. You then hit the ball another 5.0 m back to the north. What is the ball's displacement?

25 S

Calculate the average speed of a gazelle that runs 140 meters in 5.0 seconds.

28

If you travel 40 miles east and then turn around and drive 12 miles west, the displacement is?

28 miles E

If a car goes along a straight road heading east and speeds up from 45 ft/s to 60 ft/s in 5 s, calculate the acceleration.

3 E

Light travels 300,000,000 m/s, and one year has approximately 32,000,000 seconds. A light year is the distance light travels in one year. State the speed in km/s, using scientific notation.

3 x 105 km/s

Light travels 300,000,000 m/s, and one year has approximately 32,000,000 seconds. A light year is the distance light travels in one year. State the speed in m/s, using scientific notation.

3 x 108 m/s

A car travels from City A to City B to the east. It takes 2 hours, and the road mileage is 100 miles. The map shows that the cities are only 80 miles apart (straight-line distance). Calculate the average velocity.

40 E

City B is north of City A, and the 400 mile trip by car takes 8 hours. The cities are 320 miles apart in a straight line. What is the velocity of a trip from City A to City B?

40 N

Aiden takes 0.10 s to throw a baseball, which leaves his hand with a velocity of 40 m/s. The ball's acceleration is _____.

400 m/s2

You travel 20.0 mph for 0.500 hour, 40.0 mph for 1.00 hour, 30.0 mph for 0.500 hour, and 50.0 mph for 2.00 hours. What is the average speed?

41.3 mph

A car travels 35.0 mph north for 1.00 hour, then 40.0 mph east for 0.0500 hour, and finally 50.0 mph northeast for 2.00 hours. Calculate the average speed.

44.9

During a treasure hunt, Cody walks 45.0 m south and 7.50 m to the west. What single straight-line displacement could Cody have taken to reach the treasure? (Remember that magnitude and angle and direction are all needed for your answer.)

45.62 meters, 9.46 degrees towards west from south.

If a vector that is 3 cm long represents 30 km/h, what velocity does a 5 cm long vector which is drawn using the same scale represent?

50 km/h

If you travel normally 50 miles along a road as shown in the diagram, and a detour is established so that you must travel to the right and up, what is the total distance you must now travel?

70

Calculate 2 x 10-3cm ÷ 2.5 x 104cm

8 x 10-8

Rocket engineers use Newton's third law during launch. Identify the action force.

Exhaust gases push down on the earth.

A batter swings at a baseball. The action force is the bat hitting the ball with a force of 5N. The reaction force, however, cannot be determined.

False

A good model of the solar system to present to elementary children is the Ptolemaic model.

False

Since our number system is on a base-10 notation, we do not need to learn scientific notation.

False

Temperature cannot be considered a field since there are occasions where it is not possible to measure it with a thermometer.

False

A person walks along a road 2 miles and rests. Then taking another road, he travels 3 miles; and switching to a dirt path, he walks 2 miles before arriving at his destination. The distance the person has traveled is 7 miles.

True

A suitable model for air could be B-B's moving rapidly around and colliding with each other.

True

Kepler's Second Law of Motion

a line from planet to sun sweeps out equal areas in equal times

A rifle is fired and recoils when the bullet leaves the gun. This is an example of Newton's third law. The force on the bullet is

the same as that on the rifle

In the picture of a planet in orbit around its star, area A is double that of area B. What is true of the time the planet takes to travel A1A2 as compared to B1B2?

twice as much

Newton's Third Law of Motion

every action produces an equal and opposite reaction

A 2,000-kg test car, traveling 60 m/s hits a brick wall. Using motion pictures, the time involved is determined to be 0.050 s. What is the change in momentum of the car?

-1.2 x 10^5

An object is dropped near the earth's surface. At the end of 4.0 s, how fast is it falling in m/s? (Ignore air resistance.)

-39