Physics Final

C

(nineteenth figure) If the object's initial velocity is 2 m/s what will be the object's velocity after this force acts upon the object? A: 12 m/s B: 10 m/s C: 9 m/s D: 6 m/s

A

(nineteenth figure) In the diagram above, a mass m starting at point A is projected with the same initial horizontal velocity v0 along each of the three tracks shown here (with negligible friction) sufficient in each case to allow the mass to reach the end of the track at point B. (Path 1 is directed up, path 2 is directed horizontal, and path 3 is directed down.) The masses remain in contact with the tracks throughout their motions. The displacement A to B is the same in each case, and the total path length of path 1 and 3 are equal. If t1,t2, and t3 are the total travel times between A and B for paths 1, 2, and 3, respectively, what is the relation among these times? A. t3 < t2 < t1 B. t2 < t3 < t1 C. t2 < t1 = t3 D. t2 = t3 < t1

B

(nineteenth figure) What is the magnitude of the impulse of the force? A: 10 N s B: 7 N s C: 5 N s D: 1 N s

B

(fourteenth figure) What is the objects acceleration during interval t=0 to t=3 s? A: 0.4 m/s^2 B: 1 m/s^2 C: 1.5 m/s^2 D: 2 m/s^2

D

( third figure) Two people, one of mass 100 kg and the other of mass 50 kg, stand facing each other on an ice-covered (essentially frictionless) pond. If the heavier person pushes on the lighter one with a force F, then A. the force felt by the heavier person is (-1/2) F B. the force felt by the person is -2F C. the magnitude of the acceleration of the lighter person will be half of the magnitude of the acceleration of the heavier person D. the magnitude of the acceleration of the lighter person will be twice the magnitude of the acceleration of the heavier person

A

(eighteenth figure) A moon has an elliptical orbit about the planet as shown above. At point A the moon has speed vA and is at a distance rA from the planet. Which of the following correctly explains the method for determining the distance of the moon from the planet at point B in the given quantities? A: Conservation of angular momentum, because the gravitational force exerted by the moon on the planet is the same as that exerted by the planet on the moon. B: Conservation of angular momentum, because the gravitational force exerted on the moon is always directed towards the planet. C: Conservation of energy, because the gravitational force exerted on the moon is always directed towards the planet. D: Conservation of energy, because the gravitational force exerted by the moon on the planet is the same as that exerted by the planet on the moon.

A

(eighth figure) A simple pendulum executes simple harmonic motion as it swings through small angles of oscillation. If (theta max) denotes the amplitude of the oscillations, which of the following statements is true? A. When theta=0, the tangential acceleration is 0 B: When theta=(theta max), the tangential acceleration is 0 C: When theta=0, the speed is 0 D: When theta=0, the restoring force is maximized

D

(eleventh figure) A tube with one end closed and one end open resonates for a wave with wavelength λa, as shown. The next shorter wavelength at which resonance will occur is λb. The ratio of these two wavelengths λa/λb is: A: 1/4 B: 1/3 C: 3/5 D: 5/3

B

(fourteenth figure) What is the distance an object covers during the interval t=0 s to t=5 s? A: 25 m B: 16.5 m C: 15 m D: 8.5 m

B

(seventeenth figure) shows a top view of an object of mass M on a circular platform of mass 2M that is rotating counterclockwise. Assume the platform rotates without friction. Which of the following best describes an action by the object that will increase the angular speed of the entire system? A: The object moves toward the center of the platform, increasing the total angular momentum of the system. B: The object moves toward the center of the platform, decreasing the rotational inertia of the system. C: The object moves away from the center of the platform, increasing the total angular momentum of the system. D: The object moves away from the center of the platform, decreasing the rotational inertia of the system.

C

(seventh figure) If each of the resistors in the circuit has a resistance of 3 ohms, what must be the total emf of the battery if the circuit draws a total current of 3 A? A. 0.3 V B. 10 V C. 30 V D. 54 V

D

(seventh figure) Which of the following relates Pb, the rate at which energy is dissipated by resistor b, and Pe, the rate at which energy is dissipated by resistor e? A. Pb=3Pe B. Pb=9Pe C. Pe=3Pb D. Pe=9Pb

B

(sixteenth figure) 2 blocks of mass 3m and 2m attached together. The plane is frictionless and the pulley is frictionless and massless. The inclined portion of the plane creates an angle θ with the horizontal floor. What is the acceleration of the block 2m if both blocks are released from rest? A: 2mg B: 2/5gsin θ C: 2/3gsinθ D: 3/5gsinθ

D

(tenth figure) 2 charges are placed as shown at the vertices of an equilateral triangle. What is the direction of the electric field at point P? A: a B: b C: c D: d

D

(tenth figure) If a charge of +q is placed at point P, the electric field at point P would A: increase by 1/3 B: increase by 1/2 C: decrease by 1/3 D: remain the same

C

(thirteenth figure) For the circuit shown above, what is the voltage of the battery (assuming the battery has no internal resistance) A: 1 V B: 5 V C: 10 V D: 50 V

D

(twelfth figure) What is the maximum velocity of the mass? A: 0.4 m/s B: 0.8 m/s C: 1.41 m/s D: 2 m/s

C

(twelfth figure) What is the net work done as the mass falls from 0 to 8 cm? A: 80 J B: 20 J C: 0 J D: -5 J

D

(twentieth figure) Determine the total power dissipated through the circuit shown above in terms of V, R1, R2 and R3 A: V^2/R1+R2+R3 B: R1+R2+R3/V^2 C: R1(R2+R3)/V^2(R1+R2+R3) D: V^2(R1+R2+R3)/R1(R2+R3)

B

(twentieth figure) If R1 were to burn out the current coming out from the battery would A. increase B. decrease C. stay the same D. there is not current because the circuit is now incomplete

B

(twentieth figure) If V=100 V, R1= 50 ohms, R2= 80 ohms, R3= 120 ohm. Determine the voltage across R3. A: 100 V B: 60 V C: 40 V D: 20 V

D

(twenty first figure) A Wheatstone bridge is a configuration of resistors and a sensitive current meter, called a galvanometer, that is used to determine the resistance of an unknown resistor. In the Wheatstone bridge shown here, find the value of Rx, such that the current through galvanometer G is zero. A. 25 B. 15 C. 10 D. 2.5

A

(twenty second figure) 4 charges are arranged. If the magnitudes of all the charges q are all the same and the distance r between them is as shown above, what is the magnitude of the net force on the bottom right charge in terms of q, r, and k (where k=1/4piE0)? A. k(q^2/2r^2)(1+2√2) B. k(q^2/r^2)(1+√2) C. k(q^2/2r^2) D. k(q^2/r^2)

D

2 objects are sitting on a uniform stick that pivots around its center. Object 1 has a mass of 20 kg and Object 2 has a mass of 30 kg. If the Object 2 sits 1m to the left of the center of the stick, how far to the right of the center of the stick must Object 1 sit in order to balance the stick? A: 0.25 m B: 0.5 m C: 1 m D: 1.5 m

B

2 objects, A and B, have equal charge and equal mass. Neither body is in motion because the gravitational and electrostatic forces between them are equal. If the mass of Object A is halved, equilibrium will be maintained if A: the charge on Object A were doubled B: the charge on Object B were halved C: the charge on Object B were doubled D: the mass on Object B were halved

D

2 objects, a sphere and a block of the same mass, are released from rest at the top of an inclined plane. The sphere rolls down the inclined plane without slipping. The block slides down the plane without friction. Which object reaches the bottom of the ramp first? A: The sphere because it gains rotational kinetic energy but the block doesn't B: The sphere because it gains mechanical energy due to the torque exerted on it but the block doesn't C: The block because it doesn't lose mechanical energy due to friction, but the sphere does D: The block, because it doesn't gain rotational kinetic energy, but the sphere does

C

A 100 kg object is attached to a spring mounted to the ceiling with a spring coefficient of k=100 N/m. If the spring is stretched by 30 m from the initial resting position with the block attached, what is its acceleration at that point? A: 0 m/s^2 B: 10 m/s^2 C: 20 m/s^2 D: 30 m/s^2

C

A 1000 kg object is hung on a string in between two identical towers that are 340 m apart. The object sits 100 m below the height of the towers. What is the tension in the string? A: 5 kN B: 8 kN C: 10 kN D: 20 kN

B

A 4kg wooden block resting on an icy surface (so friction can be ignored) is attached to a horizontal spring (L=1m, k=100N/kg), which is attached on the other end to a vertical wall. A 2g bullet is fired at a speed of 100m/s into the wooden block, pushing it directly toward the wall. What is the period and amplitude of the resulting oscillations? A. T=1.2 s; A=45 cm B. T=1.2 s; A=1 cm C. T=0.83 s; A=45cm D. T=0.83 s ; A=21 cm

D

A spring of force constant 800 N/m is hung from a ceiling. A block of mass 4.0 kg is hung from its lower end and allowed to come to rest. How far will the block stretch the spring? A. 0.50 cm B. 1.0 cm C. 3.2 cm D. 5.0 cm

C

A ball is thrown in a projectile motion trajectory with an initial velocity v at an angle θ above the ground. If the acceleration due to gravity is -g, which of the following is the correct expression of the time it takes for the ball to reach its highest point, y, from the ground? A: v^2sint/g B: =vcosθ/g C: vsinθ/g D: v^2cosθ/g

C

A beam of monochromatic light entering a glass window pane the air will experience a change in A. frequency and wavelength B. frequency and speed C. speed and wavelength D. speed only

A

A box of mass m is sitting on an incline of 45 degrees and it requires an applied force F up the incline to get the box to begin to move. What is the max coefficient of static friction? A. (√2F/mg)-1 B. (√2F/mg) C. (√2F/mg)+1 D. (2F/mg)-1

B

A bubble in a glass of water releases from rest at the bottom of the glass and rises at acceleration a to the surface in t seconds. How much farther does the bubble travel in its last second than in its first second? A: at B: (t-1)a C: (t+1)a D: 1/2at

D

A crane lifts a shipping crate that weighs 5000 N at a constant speed of 4 m/s. At what rate is this crane doing work on the crate? A. 2000 W B. 4000 W C. 10,000 W D. 20,000 W

CD

A lightweight toy car crashes head on into a heavier toy truck. Which of the following statements is true as a result of the collision? (select 2) A: The car will experience a greater impulse than the truck B: The car will experience a greater change in momentum than the truck C: The magnitude of the acceleration experienced by the car will be greater than that experienced by the truck D: The total momentum in the collision will be conserved

AC

A mass on a spring and a simple pendulum undergo simple harmonic motion. there is no friction present for the mass on the spring. which of the following statements are true? (select 2) A: mechanical energy is constant B: the momentum of the mass is constant C: the period of the mass is constant D: the restoring force is constant

AC

A musician plucks a string on an acoustic guitar. standing waves will most likely occur in which of the following media? select 2 A: The guitar string B: the air surrounding the guitar C: the air inside the guitar D: the ground beneath the musician

A

A pair of protective headphones reduces the sound of a jet engine from 140 dB to 110 dB. What percent of the noise is being blocked? A. 99.9% B. 78.6% C. 21.4% D. 0.1%

D

A person is pulling a block of mass m with a force equal to its weight directed 30 degrees above the horizontal plane across a rough surface, generating a friction f on the block. If the person is now pushing downward on the block with the same force 30 degrees above the horizontal plane across the same rough surface, what is the friction on the block? (uk is the coefficient of kinetic friction across the surface) A: f B: 1.5f C: 2f D: 3f

B

A person standing on a horizontal floor is acted upon by 2 forces: the downward pull of gravity and the upward normal force of the floor. These 2 forces A: have equal magnitudes and form an action-reaction pair B: have equal magnitudes and do not form an action-reaction pair C: have unequal magnitudes and form an action-reaction pair D: have unequal magnitudes and do not form an action-reaction pair

B

A projectile is launched with an initial velocity of magnitude a at an angle β to the horizontal. Find its maximum vertical displacement, ignoring effects due to the air. A: (a^2sing2β)/(2g) B: (a^2sin^2β)/(2g) C: (a^2sin2β)/g D: (a^2sin^2β)/g

D

A rectangular book weighing 20 N with sides of 10 cm and 20 cm is placed on a horizontal table. Using each of your hands, you exert forces of 10 N each in opposite directions at opposite corners, such that you are pushing parallel to the shorter side in each case. What net torque are you providing to the book? A: 0 N m B: 0.5 N m C: 1 N m D: 2 N m

B

A rope of length 60 cm is tied to the handle of a bucket whose mass is 3 kg, and the bucket is then whirled in a vertical circle. At the bottom of its path, the tension in the rope is 50 N. What is the speed of the bucket at this point? A: 1 m/s B: 2 m/s C: 3 m/s D: 4 m/s

C

A rope stretched between 2 fixed points can support transverse standing waves. What is the ratio of the sixth harmonic frequency to the third harmonic frequency? A. 1/2 B. 1/√2 C. 2 D. 2 √2

D

A satellite weighs 10^4 N at ground control. What best approximates the acceleration it experiences in orbit at an altitude of twice the earth's radius? A: 111 m/s^2 B: 2.5 m/s^2 C: 2 m/s^2 D: 1.1 m/s^2

A

A simple harmonic oscillator has a frequency of 2.5 Hz and an amplitude of 0.05 m. What is the period of the oscillations? A. 0.4 s B. 0.2 s C. 8 s D. 20 s

A

A small cart of mass M is initially at rest. It collides elastically with a large cart of mass 4M and velocity v. The large cart loses half its kinetic energy to the little cart. The little cart now has a velocity of A: 1.41 v B: v C: 2v D: 4v

BD

A sound wave travels through a metal rod with a wavelength and frequency. Which 2 are true? A. when this sound wave passes into air, the frequency will change B. when this sound wave passes into air, the wavelength will change C. while in the metal rod, the wavelength and frequency have a direct relationship D. While in the metal rod, the wavelength and frequency have an inverse relationship

B

A sound wave with frequency f travels through air at speed v. With what speed will a sound wave with frequency 4f travel through the air? A. v/4 B. v C. 2v D. 4v

A

A sphere starts from rest atop a hill with a constant angle of inclination and is allowed to roll without slipping down the hill. What force provides the torque that causes the sphere to rotate? A: Static friction B: kinetic friction C: normal force fo the hill on the sphere D: gravity

A

A stopper of mass M is tied to a string of length R and swings around horizontally in uniform circular motion with a velocity of v when acted on by a force of F. What is the period of the stopper? A: √ 4pi^2MR/F B: √ MR/4pi^2F C: √ 4pi^2/FMR D: √ 4pi^2R/MF

D

A stopper of mass M is tied to a string of length R and swings around horizontally in uniform circular motion with a velocity of v when acted on by a force of F. What is the power developed by the force? A: FR B: Fv C: Mv^2 D: 0

C

A uniform bar is lying on a flat table. Besides the gravitational and normal forces (which cancel), the bar is acted upon by two other forces, F1 and F2, which are parallel to the surface of the table. If the net force on the rod is zero, then which one of the following is true? A: The net torque on the bar must also be zero B: The bar can accelerate translationally if F1 and F2 are not applied at the same point C: The net torque will be zero if F1 and F2 are applied at the same point D: The bar cannot accelerate translationally or rotationally

C

An alarm whose frequency is 400 Hz is dropped out of a third floor window. The student who drops it measures the frequency with a very sensitive oscilloscope. The measured frequency A: appears higher than 400 Hz and the frequency increases as if falls B: appears higher than 400 Hz and the frequency decreases as it falls C: appears lower than 400 Hz and the frequency decreases as it falls D: appears lower than 400 Hz and the frequency increases as it falls

B

An astronaut lands on a planet whose mass and radius are each twice that of Earth. If the astronaut weights 800 N on Earth, how much will he weigh on this planet? A. 200 N B. 400 N C. 800 N D. 1600 N

D

An electric dipole consists of a pair of equal but opposite point charges of magnitude 4.0 nC separated by a distance of 2.0 cm. What is the electric field strength at the point midway between the charges? A. 0 B. 9.0 x 10^4 N/C C. 1.8 X 10^5 N/C D. 7.2 X 10^5 N/C

D

An elevator has a mass of 500 kg. It may safely carry an additional mass of 1000 kg and accelerate upward at 2 m/s^2. What's the tension in the cables under max conditions? A: 4900 N B: 9800 N C: 14700 N D: 18000 N

A

An object (mass = m) above the surface of the Moon (mass = m) is dropped from an altitude h equal to the Moon's radius (R). What is the object's impact speed? A. √GM/R B. √GM(2R) C. √2GM/R D. √2GMm/R

C

An object begins at rest at the top of an inclined frictionless plane with a height of 125 m and a horizontal length (not the hypotenuse) of 200 m. What will be the speed of the object at the end of the inclined plane? A. 235 m/s B. 100 m/s C. 50 m/s D. 23.5 m/s

D

An object has a kinetic energy of K. If the speed of the object were doubled what would be the resulting kinetic energy? A. 1/2K B. K C. 2K D. 4K

B

An object is thrown horizontally off a high cliff at 7.5 m/s (assume altitude near sea level and neglect air resistance). what is displacement after 2 seconds? A: 27.5 m B: 25 m C: 20 m D: 15 m

D

An object is thrown with an initial speed of 7 m/s directed 45 degrees above the horizontal from a cliff. After reaching the peak of its trajectory, it falls 20 m to the ground below. What is the approximate ratio of the time it takes to hit the ground from the peak of the trajectory to the time it takes from its release to the peak of the trajectory? A: 0.5 B: 1 C: 2 D: 4

C

An object of 100 kg rests on a horizontal floor. The coefficient of static friction is us=0.4 between the object and the floor. If a constant force of 250 N is pushed horizontally on the object, what is the magnitude of the force of static friction? A. 400 N B. 350 N C. 250 N D. 150 N

D

An object of mass 3 kg is undergoing uniform circular motion. The object's speed is 4 m/s, and the radius of the path is 0.5 m. How much work is done on this object by the centripetal force? A. 50 J B. 12 J C. 6 J D. 0 J

D

An object of mass 5 kg is acted upon by exactly four forces, each of magnitude 10 N. Which of the following could NOT be the resulting acceleration of the object? A. 0 m/s^2 B. 4 m/s^2 C. 8 m/s^2 D. 10 m/s^2

C

An object of mass m (Object 1) moving with speed v collides head on with a target object of mass 2m (Object 2) initially at rest. If the collision is perfectly inelastic, what fraction of Object 1's initial kinetic energy is lost? A: 1/9 B: 1/6 C: 2/3 D: 4/5

AD

An object traveling at x m/s can stop at a distance d m with a max negative acceleration. If the car is traveling at 2x m/s, which 2 statements are true? A. stopping time is doubled B. stopping time is quadrupled C. stopping distance is doubled D. stopping distance is quadrupled

D

At a distance of 20m from a source of sound, the sound level is 40 dB...observer backs up 40m from the new source, what will the sound level be? A. 14 dB B. 20 dB C. 28 dB D. 34 dB

B

Consider the above configuration of masses attached via a massless rope and pulley over a frictionless inclined plane (fifteenth figure). What is the acceleration of the masses? A: (m1-m2)g/(m1+m2) B: (m1-m2sinθ)g/(m1+m2) C: (m1-m2cosθ)g/(m1+m2) D: g

B

How much current does a 60 W light bulb draw if it operates at a voltage of 120 V? A. 0.25 A B. 0.5 A C. 2A D. 4A

D

If L, M and T denote the dimensions of length, mass, and time, respectively, what are the dimensions of power? A. L^2M/T^2 B. M^2L/T^2 C. L^2M/T^3 D. ML^2/T^3

AC

If the acceleration of an object is not zero, then which of the following could be constant? (select 2) A: Speed B: Linear momentum C: kinetic energy D: velocity

A

If the coefficient of friction between the block and the incline is 0.4, how much work is done by the normal force on the block as it slides down the full length of the incline? (first figure) A. 0 J B. 2.0 J C. 4.0 J D. 4.9 J

D

If the rod in the figure above (sixth figure) is uniform and has mass m, what is the tension in the supporting string? The rod is free to rotate about point P A. 1/2mgsin(theta) B. mgsin(theta) C. 1/2mgcos(theta) D. 1/2mg

D

If the surface of the incline is frictionless, how long will the block take to reach the bottom if it was released from rest at the top? (first figure) A. 0.5 s B. 1.0 s C. 1.4 s D. 2.0 s

B

If the surface of the incline is frictionless, with what speed will the block reach the bottom if it was released from rest at the top? (first figure) A. 8 m/s B. 10 m/s C. 14 m/s D. 18 m/s

C

In the figure above, the coefficient of sliding friction between the small block and the tabletop is 0.2. If the pulley is frictionless and massless, what will be the acceleration of the block once they are released from rest? (second figure) A. 0.5 g B. 0.6 g C. 0.7 g D. 0.8 g

D

In the graph above (ninth figure) the instantaneous velocity at 9 seconds is closest to A: 4/9 m/s B: -4/9 m/s C: 11/4 m/s D: -11/4 m/s

C

In which of the following situations involving a source of sound and a detector of the sound is it possible that there is NO perceived Doppler shift? A. The source travels toward the stationary detector. B. The detector travels toward the stationary source. C. Both the source and detector travel in the same direction. D. Both the source and detector travel in opposite directions, with the source and detector moving away from each other.

BC

N resistors (N is greater than 2) are connected in parallel with a battery of voltage V0. If one of the resistors is removed from the circuit, which 2 of the following quantities will decrease? A. voltage across any of the remaining resistors B. current output by the battery C. total power dissipated in the circuit D. voltage supplied by the battery

C

Object 1 of mass 0.25 kg moves at 10 m/s towards Object 2 initially at rest of mass 0.25 kg. The resulting collision is perfectly inelesatic, what is the speed of the objects after the collision? A: 0 m/s B: 2.5 m/s C: 5 m/s D: 7.5 m/s

C

Sound waves travel at 350 m/s through warm air and at 3500 m/s through brass. What happens to the wavelength of a 700 Hz acoustic wave as it enters brass from warm air? A. It decreases by a factor of 20 B. It decreases by a factor of 10 C. It increases by a factor of 10 D. The wavelength remains unchanged

B

The Sun is approximately 150 million km from the Earth. A year - the time for 1 revolution of the earth around the Sun- is roughly pi X 10^7 seconds. Assuming a circular orbit, what best approximates the avg acceleration of the Earth due to the sun? A: 6 X 10^-6 m/s^2 B: 6 X 10^-3 m/s^2 C: 4 X 10^2 m/s^2 D: 4 X 10^19 m/s^2

AD

The electric field strength in a vacuum at a point at a distance from a source change is NOT dependent on which of the following? (select 2) A: another charge placed at that point B: the magnitude of the source change C: the distance from the source change D: The sign of the source change

A

The figure above shows 2 positively charged particles. The +Q charge is fixed in position, and the +q charge is brought close to +Q and released from rest. Which of the following graphs best depicts the acceleration of the +q charge as a function of its distance r from +Q? (fourth figure)

B

The figure above shows a plane diagram. The figure shows four point charges arranged at the corners of a square with point B as its center. A positive charge would experience no net force if it were placed at which of the three points shown in the figure (fifth figure) A. A only B. B only C. C only D. A, B, or C

A

The gravitational force the sun exerts on the earth is F. Mars is 1.5 times from the Sun than the earth and its mass is 1/6 of earth's mass. What is the gravitational force that the sun exerts on Mars? A: 2/27F B: 1/9F C: 9F D: 27/2F

B

Two equally positive charges are r distance apart. If the amount of charge on one is doubled and the distance between the charges is doubled, what is the ratio of new electric force to old electric force? A. 1/4 B. 1/2 C. 2 D. 4

B

Two satellites are in circular orbit around the Earth. The distance from Satellite 1 to Earth's center is r, and the distance from Satellite 2 to the Earth's center is r2, what is the speed of Satellite 2? A. v1√r2/r1 B. v1√r1/r2 C. v1(r2/r1) D. v1(r1/r2)^2

A

Two traveling waves of equal frequency, one of amplitude 4 cm and the other of amplitude 6 cm, superimpose in a single medium. Which of the following best describes the displacement, D, of the resultant wave? A: 2 cm ≤ D ≤ 10 cm B: D=5cm C: D=10cm D: 10 cm ≤ D ≤ 12 cm

D

What happens to the force of gravitational attraction between two small objects if the mass of each object is doubled and the distance between their centers is doubled? A. It is doubled B. It is quadrupled C. It is halved D. It remains the same

AB

Which 2 of the following statements will increase the resistance of a closed circuit system? A. replacing the wire with 1 that has a smaller cross section area B. adding a voltmeter to the wire C. halving the wire length in the close circuit D. adding another resistor in parallel with the current resistor in a closed circuit

C

Which of the following changes to a circuit will always bring about an increase in the current? A: Increased voltage and increased resistance B: Decreased voltage and decreased resistance C: Increased voltage and decreased resistance D: Decreased voltage and increased resistance

D

Which of the following concerning uniform circular motion is true? A: The centrifugal force is the action-reaction pair of the centripetal force B: the centripetal acceleration of the object is constant C: the velocity of the object in motion changes whereas the acceleration of the object is constant D: a satellite undergoing uniform circular motion is falling towards the center in a circular path

B

Wire 1 has 3 times the length and twice the diameter of Wire 2. If both wires are made of the same material and if R1 is the resistance of Wire 1 and R2 is the resistance of Wire 2, then which of the following is true? A. R2=(2/3)R1 B: R2=(4/3)R1 C. R2=6R1 D: R2=12R1

A

Wire Y is made of the same material but has twice the diameter and half the length of Wire X. If Wire X has a resistance of R, then Wire Y would have a resistance of A: R/8 B: R/2 C: R D: 2R

D

You are standing on a railroad track as a train approaches at a constant velocity. Suddenly the engineer sees you, applies the brakes, and sounds the whistle. Which of the following describes the sound of the whistle as you hear it starting from that moment? A. loudness increasing, pitch increasing B. loudness increasing, pitch constant C. loudness decreasing, pitch increasing D. loudness increasing, pitch decreasing

CD

a 2 kg mass is attached to a massless, 0.5 m string and is used as a simple pendulum by extending it to an angle theta=5 degrees and allowing it to oscillate. Which of the following changes will change the period of the pendulum? (select 2) A. replacing mass with a 1 kg mass B. changing the initial extension of the pendulum to a 10 degree angle C. replacing the string with a 0.25 m string D. moving the pendulum to the surface of the Moon

C

a 50 kg block resting on flat ground is attached by a hook at the center of its top face to a rope, which is then pulled by a man such that it makes an angle of 30 degrees with the horizontal. If the man pulls with a force of 200 N and the coefficient of kinetic friction between the block and the ground is 0.2, what horizontal acceleration does the block undergo? A: 3. 2 m/s^2 B: 2.8 m/s^2 C: 1.9 m/s^2 D: 1.4 m/s^2