Question 1

In a real collision,

Accepted Answer

A) kinetic energy is conserved. 
B) linear momentum is conserved in the absence of external forces. 
C) both momentum and kinetic energy are conserved. 
D) neither momentum nor kinetic energy is conserved. 
E) the extent to which momentum and kinetic energy are conserved depends on the coefficient of restitution. 
A) kinetic energy is conserved. 
B) linear momentum is conserved in the absence of external forces. 
C) both momentum and kinetic energy are conserved. 
D) neither momentum nor kinetic energy is conserved. 
E) the extent to which momentum and kinetic energy are conserved depends on the coefficient of restitution.

Question 2

A bullet (mass = m1)is fired at speed V into a block of mass m2 at rest.If the bullet escapes from the block with only a third of its original speed then the recoil speed of the block is given by

Accepted Answer

A) m1V/ 3m2  
B) 2m1V/ 3m2  
C) m2V/ 3m1  
D) 2m2V/ 3m1  
E) 4m2V/ 9m1  
A) m1V/ 3m2  
B) 2m1V/ 3m2  
C) m2V/ 3m1  
D) 2m2V/ 3m1  
E) 4m2V/ 9m1

Question 3

A 40 kg boy,on a stunt,jumps from one ice sled to another sled placed next to the first one,and then quickly jumps back to the first one.The horizontal speed relative to the ice for each jump is 2 m/s and the mass of each sled is 20 kg.What is the speed of the second sled after the second jump? Assume that there is no friction between the sled and the ice.

Accepted Answer

A) 1 m/s 
B) 2 m/s 
C) 3 m/s 
D) 4 m/s 
E) 8 m/s 
A) 1 m/s 
B) 2 m/s 
C) 3 m/s 
D) 4 m/s 
E) 8 m/s

Question 4

Cyrano de Bergerac,in the play by Edmond Rostand,claims to have invented six methods of reaching the moon.Five of these are listed below.Select the one that has a physically sound basis.

Accepted Answer

A) "Adorn my form with crystal vials filled with morning dew,and so be drawn aloft as the sun rises." 
B) "Sealing up the air in a cedar chest,rarefy it by means of mirrors placed in an icosahedron." 
C) "Construct the form of a huge locust,driven upward by leaps and bounds by impulses due to pellets of saltpeter ejected from the rear." 
D) "Smoke,having a natural tendency to rise,blow in a globe enough to raise me." 
E) "Seated on an iron plate,I hurl a magnet in the air-the iron follows-I catch the magnet-throw again-and so proceed indefinitely." 
A) "Adorn my form with crystal vials filled with morning dew,and so be drawn aloft as the sun rises." 
B) "Sealing up the air in a cedar chest,rarefy it by means of mirrors placed in an icosahedron." 
C) "Construct the form of a huge locust,driven upward by leaps and bounds by impulses due to pellets of saltpeter ejected from the rear." 
D) "Smoke,having a natural tendency to rise,blow in a globe enough to raise me." 
E) "Seated on an iron plate,I hurl a magnet in the air-the iron follows-I catch the magnet-throw again-and so proceed indefinitely."

Question 5

Use the picture to the right to answer the next question. A puck of mS1U1B11S1U1B0 and moving with velocity vS1U1B11S1U1B0 collides elastically with a second puck of mass mS1U1B12S1U1B0, which is initially at rest. After the collision, mS1U1B11S1U1B0 moves with velocity vS1U1B11S1U1B0’ at an angle α below the x axis and mS1U1B12S1U1B0 moves with velocity vS1U1B12S1U1B0’ at an angle θ above the x axis.
 
-The conservation of momentum along the x direction can be written as

Accepted Answer

A) m1 v1 = m1v1' cos $\alpha$ + m2v2' cos $\theta$ 
B) 0 = m1v1' cos $\alpha$ + m2v2' cos $\theta$ 
C) m1 v1 = m1v1' sin $\alpha$  + m2v2' sin $\theta$ 
D) 0 = m1v1' sin $\alpha$ + m2v2' sin $\theta$ 
E) none of the above 
A) m1 v1 = m1v1' cos $\alpha$ + m2v2' cos $\theta$ 
B) 0 = m1v1' cos $\alpha$ + m2v2' cos $\theta$ 
C) m1 v1 = m1v1' sin $\alpha$  + m2v2' sin $\theta$ 
D) 0 = m1v1' sin $\alpha$ + m2v2' sin $\theta$ 
E) none of the above

Question 6

A woman on a spaceship traveling at a velocity   0 in free space runs forward and then suddenly stops.When she stops,the center of mass of the system (that is,the ship and the woman)

Accepted Answer

A) moves in the same direction as   0 with a slight increase in speed. 
B) moves in the same direction as   0 with a slight decrease in speed. 
C) comes to rest if the woman can run fast enough. 
D) continues unchanged at a velocity   0. 
E) moves in the direction that the woman runs until she stops. 
A) moves in the same direction as   0 with a slight increase in speed. 
B) moves in the same direction as   0 with a slight decrease in speed. 
C) comes to rest if the woman can run fast enough. 
D) continues unchanged at a velocity   0. 
E) moves in the direction that the woman runs until she stops.

Question 7

Use the picture to the right to answer the next question. A puck of mS1U1B11S1U1B0 and moving with velocity vS1U1B11S1U1B0 collides elastically with a second puck of mass mS1U1B12S1U1B0, which is initially at rest. After the collision, mS1U1B11S1U1B0 moves with velocity vS1U1B11S1U1B0’ at an angle α below the x axis and mS1U1B12S1U1B0 moves with velocity vS1U1B12S1U1B0’ at an angle θ above the x axis.
 
-Which of the following statements is true?

Accepted Answer

A) Momentum is conserved in the x direction. 
B) Momentum is conserved in the y direction. 
C) The total momentum before equals the total momentum after the collision. 
D) The kinetic energies are conserved. 
E) All of the above statements are true. 
A) Momentum is conserved in the x direction. 
B) Momentum is conserved in the y direction. 
C) The total momentum before equals the total momentum after the collision. 
D) The kinetic energies are conserved. 
E) All of the above statements are true.

Question 8

Use the scenario below for the next question.
You were traveling north at speed vc in your car of mass mS1U1B1cS1U1B0 = 2000 kg through an intersection when you were struck by a light truck of mass mS1U1B1tS1U1B0 = 4000 kg traveling West. After the collision the two vehicles are stuck together and travel a distance of 20 m in the direction 30° N of W.
-What is the truck speed in terms of vc?

Accepted Answer

A) 0.5vc 
B) 0.75vc 
C) 0.87vc 
D) vc 
E) 1.15vc 
A) 0.5vc 
B) 0.75vc 
C) 0.87vc 
D) vc 
E) 1.15vc

Question 9

Momentum is conserved in which of the following?

Accepted Answer

A) elastic collisions 
B) inelastic collisions 
C) explosions 
D) collisions between automobiles 
E) All of these are correct. 
A) elastic collisions 
B) inelastic collisions 
C) explosions 
D) collisions between automobiles 
E) All of these are correct.

Question 10

A Saturn V rocket with an initial mass m0 of 3 $\times$ 106 kg has a payload that accounts for 27% of this mass,a burn rate of 15 $\times$ 103 kg/s,and a thrust Fth of 35 $\times$ 106 N.The exhaust speed is

Accepted Answer

A) 1.46 km/s 
B) 1.85 km/s 
C) 2.09 km/s 
D) 2.33 km/s 
E) 2.54 km/s 
A) 1.46 km/s 
B) 1.85 km/s 
C) 2.09 km/s 
D) 2.33 km/s 
E) 2.54 km/s

Question 11

Two students,sitting on frictionless carts,push against each other.Both are initially at rest and the mass of student 1 and the cart is M,and that of student 2 and the cart is 1.5M.If student 1 pushes student 2 so that she recoils with velocity   ,what is the velocity of student 2.

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 12

A particle of mass m moving at 5.0 m/s in the positive x direction makes a glancing elastic collision with a particle of mass 2m that is at rest before the collision.After the collision,m moves off at an angle of 45º to the x axis and 2m moves off at 60º to the x axis.The speed of m after the collision is

Accepted Answer

A) 4.5 m/s 
B) 2.5 m/s 
C) 3.3 m/s 
D) 1.8 m/s 
E) 1.1 m/s 
A) 4.5 m/s 
B) 2.5 m/s 
C) 3.3 m/s 
D) 1.8 m/s 
E) 1.1 m/s

Question 13

A 40-kg girl,standing at rest on the ice,gives a 60-kg boy,who is also standing at rest on the ice,a shove.After the shove,the boy is moving backward at 2.0 m/s.Ignore friction.The girl's speed is

Accepted Answer

A) zero 
B) 1.3 m/s 
C) 2.0 m/s 
D) 3.0 m/s 
E) 6.0 m/s 
A) zero 
B) 1.3 m/s 
C) 2.0 m/s 
D) 3.0 m/s 
E) 6.0 m/s

Question 14

A ball with a mass of 50 g is dropped from a point 5.41 m above a sidewalk.The ball is in contact with the sidewalk for 8.1 $\times$10-3 s.What is the magnitude of the average force exerted on the ball?

Accepted Answer

A) 0.12 kN 
B) 89 N 
C) 9.2 N 
D) 0.49 N 
E) It cannot be determined without knowing how high the ball bounces. 
A) 0.12 kN 
B) 89 N 
C) 9.2 N 
D) 0.49 N 
E) It cannot be determined without knowing how high the ball bounces.

Question 15

Two cars of equal mass travel in opposite directions at equal speeds.They collide in a perfectly inelastic collision.Just after the collision,their velocities are

Accepted Answer

A) zero. 
B) equal to their original velocities. 
C) equal in magnitude but opposite in direction to their original velocities. 
D) less in magnitude and in the same direction as their original velocities. 
E) less in magnitude and opposite in direction to their original velocities. 
A) zero. 
B) equal to their original velocities. 
C) equal in magnitude but opposite in direction to their original velocities. 
D) less in magnitude and in the same direction as their original velocities. 
E) less in magnitude and opposite in direction to their original velocities.

Question 16

A golf ball and a Ping-Pong ball are dropped in a vacuum chamber.When they have fallen halfway to the floor,they have the same

Accepted Answer

A) speed. 
B) potential energy. 
C) kinetic energy. 
D) momentum. 
E) speed,potential energy,kinetic energy,and momentum. 
A) speed. 
B) potential energy. 
C) kinetic energy. 
D) momentum. 
E) speed,potential energy,kinetic energy,and momentum.

Question 17

Two masses,m1 and m2,are moving with velocities   and   when they collide.After the collision,the final velocities are   and   .Which of the following expressions is true? (The subscripts x and y represent the components along x and y respectively.)

Accepted Answer

A)    
B)    
C)    
D)    
E) (
A) and (
B)  
A)    
B)    
C)    
D)    
E) (
A) and (
B)

Question 18

The center of mass of a system of particles is so defined that

Accepted Answer

A) it is always at rest. 
B) it is always at rest or moving with constant velocity. 
C) it always moves in a straight line even if the particles are rotating about it. 
D) the kinetic energy of the system is a maximum about any axis through the center of mass. 
E) its location depends only on the masses of the particles and their locations. 
A) it is always at rest. 
B) it is always at rest or moving with constant velocity. 
C) it always moves in a straight line even if the particles are rotating about it. 
D) the kinetic energy of the system is a maximum about any axis through the center of mass. 
E) its location depends only on the masses of the particles and their locations.

Question 19

Two balls are dropped from a height of 6 m.Ball A bounces up to a height of 4 m whereas ball B bounces up to 2 m.Which ball experiences the larger impulse during its collision with the floor?

Accepted Answer

A) ball A 
B) ball B 
C) They both experience the same impulse. 
D) It is impossible to tell without knowing the masses of the balls. 
E) It is impossible to tell without knowing the durations of the collisions. 
A) ball A 
B) ball B 
C) They both experience the same impulse. 
D) It is impossible to tell without knowing the masses of the balls. 
E) It is impossible to tell without knowing the durations of the collisions.

Question 20

An object of mass M1 is moving with a speed v on a straight,level,frictionless track when it collides with another mass M2 that is at rest on the track.After the collision,M1 and M2 stick together and move with a speed of

Accepted Answer

A) v 
B) M1v 
C) (M1 + M2)v/M1  
D) M1v/(M1 + M2) 
E) M1v/M2  
A) v 
B) M1v 
C) (M1 + M2)v/M1  
D) M1v/(M1 + M2) 
E) M1v/M2

Exam 8: Systems of Particles and Conservation of Linear Momentum

In a real collision,

A bullet (mass = m1)is fired at speed V into a block of mass m2 at rest.If the bullet escapes from the block with only a third of its original speed then the recoil speed of the block is given by

Cyrano de Bergerac,in the play by Edmond Rostand,claims to have invented six methods of reaching the moon.Five of these are listed below.Select the one that has a physically sound basis.

A woman on a spaceship traveling at a velocity 0 in free space runs forward and then suddenly stops.When she stops,the center of mass of the system (that is,the ship and the woman)

Momentum is conserved in which of the following?

A Saturn V rocket with an initial mass m0 of 3 ×\times× 106 kg has a payload that accounts for 27% of this mass,a burn rate of 15 ×\times× 103 kg/s,and a thrust Fth of 35 ×\times× 106 N.The exhaust speed is

Two students,sitting on frictionless carts,push against each other.Both are initially at rest and the mass of student 1 and the cart is M,and that of student 2 and the cart is 1.5M.If student 1 pushes student 2 so that she recoils with velocity ,what is the velocity of student 2.

A 40-kg girl,standing at rest on the ice,gives a 60-kg boy,who is also standing at rest on the ice,a shove.After the shove,the boy is moving backward at 2.0 m/s.Ignore friction.The girl's speed is

A ball with a mass of 50 g is dropped from a point 5.41 m above a sidewalk.The ball is in contact with the sidewalk for 8.1 ×\times× 10-3 s.What is the magnitude of the average force exerted on the ball?

Two cars of equal mass travel in opposite directions at equal speeds.They collide in a perfectly inelastic collision.Just after the collision,their velocities are

A golf ball and a Ping-Pong ball are dropped in a vacuum chamber.When they have fallen halfway to the floor,they have the same

Two masses,m1 and m2,are moving with velocities and when they collide.After the collision,the final velocities are and .Which of the following expressions is true? (The subscripts x and y represent the components along x and y respectively.)

The center of mass of a system of particles is so defined that

Two balls are dropped from a height of 6 m.Ball A bounces up to a height of 4 m whereas ball B bounces up to 2 m.Which ball experiences the larger impulse during its collision with the floor?

An object of mass M1 is moving with a speed v on a straight,level,frictionless track when it collides with another mass M2 that is at rest on the track.After the collision,M1 and M2 stick together and move with a speed of

Systems of Measurement

Motion in One Dimension

Motion in Two and Three Dimensions

Newtons Laws

Applications of Newtons Laws

Work and Energy

Conservation of Energy

Rotation

Conservation of Angular Momentum

Gravity

Static Equilibrium and Elasticity

Fluids

Oscillations

Wave Motion

Superposition and Standing Waves

Temperature and the Kinetic Theory of Gases

Heat and the First Law of Thermodynamics

The Second Law of Thermodynamics

Thermal Properties and Processes

The Electric Field I: Discrete Charge Distributions

The Electric Field Ii: Continuous Charge Distributions

Electric Potential

Capacitance

Electric Current and Direct-Current Circuits

The Magnetic Field

Sources of the Magnetic Field

Magnetic Induction

Alternating-Current Circuits

Maxwells Equations and Electromagnetic Waves

Properties of Light

Optical Images

Interference and Diffraction

Wave Particle Duality and Quantum Physics

Applications of the Schrodinger Equation

Atoms

Molecules

Solids and the Theory of Conduction

Relativity

Nuclear Physics

Elementary Particles and the Beginning of the Universe

Filters

A bullet (mass = m₁)is fired at speed V into a block of mass m₂ at rest.If the bullet escapes from the block with only a third of its original speed then the recoil speed of the block is given by

A woman on a spaceship traveling at a velocity ₀ in free space runs forward and then suddenly stops.When she stops,the center of mass of the system (that is,the ship and the woman)

A Saturn V rocket with an initial mass m₀ of 3 $\times$ 10⁶ kg has a payload that accounts for 27% of this mass,a burn rate of 15 $\times$ 10³ kg/s,and a thrust F_th of 35 $\times$ 10⁶ N.The exhaust speed is

A ball with a mass of 50 g is dropped from a point 5.41 m above a sidewalk.The ball is in contact with the sidewalk for 8.1 $\times$ 10^-3 s.What is the magnitude of the average force exerted on the ball?

Two masses,m₁ and m₂,are moving with velocities and when they collide.After the collision,the final velocities are and .Which of the following expressions is true? (The subscripts x and y represent the components along x and y respectively.)

An object of mass M₁ is moving with a speed v on a straight,level,frictionless track when it collides with another mass M₂ that is at rest on the track.After the collision,M₁ and M₂ stick together and move with a speed of