Question 1

A baseball infielder,mass 78.0 kg,jumps up with velocity 3.50 m/s and catches a 0.195-kg baseball moving horizontally at 55.0 m/s.Of the following,which is closest to the final momentum of the system,infielder and baseball?

Accepted Answer

A) 273 kg⋅m/s 
B) 328 kg⋅m/s 
C) 284 kg⋅m/s 
D) 240 kg⋅m/s 
E) 293 kg⋅m/s

Question 2

A man standing on frictionless ice throws a 1.00-kg mass at 29.0 m/s at an angle of elevation of 50.0°.What was the magnitude of the man's momentum immediately after throwing the mass?

Accepted Answer

A) 45.1 kg·m/s 
B) 18.6 kg·m/s 
C) 22.2 kg·m/s 
D) 37.9 kg·m/s 
E) This cannot be answered because the mass of the man needs to be known.

Question 3

The kinetic energy of an object is quadrupled.Its momentum will change by what factor?

Accepted Answer

A) zero 
B) two 
C) eight 
D) four

Question 4

In a two-body collision,if the kinetic energy of the system is conserved,then which of the following best describes the momentum after the collision?

Accepted Answer

A) must be less 
B) must also be conserved 
C) may also be conserved 
D) is doubled in value

Question 5

Neglecting gravity,doubling the exhaust velocity from a single stage rocket initially at rest changes the final kinetic energy of the burnout stage by what factor? Assume all other variables,such as the mass of the rocket and the mass of the fuel,do not change.

Accepted Answer

A) It is the same. 
B) It doubles. 
C) It quadruples. 
D) It increases by a factor of 1.693.

Question 6

In an automobile collision,how does an airbag lessen the blow to the passenger? Assume as a result of the collision,the passenger stops.

Accepted Answer

A) The air bag decreases the momentum change of the passenger in the collision. 
B) During the collision,the force from the air bag is greater than would be the force from the windshield or dashboard so the passenger cannot hit the hard objects. 
C) The stopping impulse is the same for either the hard objects or the airbag.Unlike the windshield or dashboard,the air bag increases the time for the slowing process and thus decreases the average force on the passenger. 
D) The airbag is there to insure the seatbelt holds.

Question 7

The dimensional equivalence of the quantity "momentum" in terms of the fundamental quantities (mass,length,time)is:

Accepted Answer

A) MLT−1. 
B) ML2T−2. 
C) MLT. 
D) MLT−2.

Question 8

An object of mass m moving at speed v0 strikes an object of mass 2m which had been at rest.The first object bounces backward along its initial path at speed v0.Is this collision elastic,and if not,what is the change in kinetic energy of the system?

Accepted Answer

A) The collision is elastic. 
B) The kinetic energy decreases by mv2. 
C) The kinetic energy decreases by mv2/2. 
D) The kinetic energy increases by mv2.

Question 9

A ball with original momentum +7.0 kg⋅m/s hits a wall and bounces straight back without losing any kinetic energy.The change in momentum of the ball is:

Accepted Answer

A) 0. 
B) 14 kg⋅m/s. 
C) 7.0 kg⋅m/s. 
D) -14 kg⋅m/s. 
E) -7.0 kg⋅m/s.

Question 10

An unfueled 1000-kg experimental rocket sled at rest on level frictionless rails is loaded with 50 kg of propellant.It exhausts the propellant in a 20 s "burn." The rocket moves at 160 m/s after the burn.What average force is experienced by the rocket during the burn?

Accepted Answer

A) 0.80 × 104 N 
B) 0.75 × 104 N 
C) 0.60 × 104 N 
D) 0.35 × 104 N

Question 11

Two particles collide,one of them initially being at rest.Is it possible for both particles to be at rest after the collision?

Accepted Answer

A) If the collision is perfectly inelastic,then this happens. 
B) If the collision is elastic,then this happens. 
C) This can happen sometimes if the more massive particle was at rest. 
D) No.

Question 12

Two masses m1 and m2,with m1 2,have momenta with equal magnitudes.How do their kinetic energies compare?

Accepted Answer

A) KE1 2 
B) KE1 = KE2 
C) KE1 > KE2 
D) More information is needed.

Question 13

Two objects,one less massive than the other,collide elastically and bounce back after the collision.If the two originally had velocities that were equal in size but opposite in direction,then which one will be moving faster after the collision?

Accepted Answer

A) The less massive one. 
B) The more massive one. 
C) The speeds will be the same after the collision. 
D) There is no way to be sure without the actual masses.

Question 14

A machine gun is attached to a railroad flatcar that rolls with negligible friction.If the railroad car has a mass of 6.35 × 104 kg,how many bullets of mass 35.0 g would have to be fired at 200 m/s off the back to give the railroad car a forward velocity of 0.56 m/s?

Accepted Answer

A) 5.1E-4 
B) 2.0E+3 
C) 6.5E+5 
D) 5.1E+3 
E) 6.5E+4

Question 15

A railroad freight car,mass 15 000 kg,is allowed to coast along a level track at a speed of 3.0 m/s.It collides and couples with a 54 000-kg loaded second car,initially at rest and with brakes released.What percentage of the initial kinetic energy of the 15 000-kg car is preserved in the two-coupled cars after collision?

Accepted Answer

A) 78% 
B) 22% 
C) 18% 
D) 38% 
E) 14%

Question 16

A model car is propelled by a cylinder of carbon dioxide gas.The cylinder emits gas at a rate of 5.00 g/s with an exit speed of 80.0 m/s.The car has a mass of 455 g,including the CO2 cylinder.Starting from rest,what is the car's initial acceleration?

Accepted Answer

A) 0.879 m/s2 
B) 40.0 m/s2 
C) 36.4 m/s2 
D) 7.28 m/s2 
E) 1.38 m/s2

Question 17

The units of impulse are equivalent to:

Accepted Answer

A) those of energy. 
B) N⋅m. 
C) kg⋅m/s. 
D) those of force.

Question 18

A disk of mass m moving in the positive x direction collides with a stationary disk,also of mass m.The first disk moves in a direction θ1 with respect to the x axis,and the second disk moves off in a direction of θ2 below the x axis,as shown in the figure. 
If v = 10 m/s,θ1 = 30°,and v1f = 8 m/s,what is v2f?

Accepted Answer

A) 6.9 m/s 
B) 6.1 m/s 
C) 2.0 m/s 
D) 8.7 m/s

Question 19

A 1 500-kg experimental rocket sled at rest on level frictionless rails is loaded with 55.0 kg of propellant.It exhausts the propellant in a 20-s "burn." The rocket moves at 155 m/s after the burn.What average force is experienced by the rocket during the burn?

Accepted Answer

A) 4.26E+2 N 
B) 1.16E+4 N 
C) 1.21E+4 N 
D) 1.94E+2 N 
E) ​2.33E+5 N

Question 20

The law of conservation of momentum is applicable to systems made up of objects described by which of the following?

Accepted Answer

A) macroscopic 
B) microscopic 
C) interacting through friction 
D) All the above choices are valid.

Exam 6: Momentum, Impulse, and Collisions

A baseball infielder,mass 78.0 kg,jumps up with velocity 3.50 m/s and catches a 0.195-kg baseball moving horizontally at 55.0 m/s.Of the following,which is closest to the final momentum of the system,infielder and baseball?

A man standing on frictionless ice throws a 1.00-kg mass at 29.0 m/s at an angle of elevation of 50.0°.What was the magnitude of the man's momentum immediately after throwing the mass?

The kinetic energy of an object is quadrupled.Its momentum will change by what factor?

In a two-body collision,if the kinetic energy of the system is conserved,then which of the following best describes the momentum after the collision?

Neglecting gravity,doubling the exhaust velocity from a single stage rocket initially at rest changes the final kinetic energy of the burnout stage by what factor? Assume all other variables,such as the mass of the rocket and the mass of the fuel,do not change.

In an automobile collision,how does an airbag lessen the blow to the passenger? Assume as a result of the collision,the passenger stops.

The dimensional equivalence of the quantity "momentum" in terms of the fundamental quantities (mass,length,time) is:

An object of mass m moving at speed v₀ strikes an object of mass 2m which had been at rest.The first object bounces backward along its initial path at speed v₀.Is this collision elastic,and if not,what is the change in kinetic energy of the system?

A ball with original momentum +7.0 kg⋅m/s hits a wall and bounces straight back without losing any kinetic energy.The change in momentum of the ball is:

An unfueled 1000-kg experimental rocket sled at rest on level frictionless rails is loaded with 50 kg of propellant.It exhausts the propellant in a 20 s "burn." The rocket moves at 160 m/s after the burn.What average force is experienced by the rocket during the burn?

Two particles collide,one of them initially being at rest.Is it possible for both particles to be at rest after the collision?

Two masses m₁ and m₂,with m₁ < m₂,have momenta with equal magnitudes.How do their kinetic energies compare?

Two objects,one less massive than the other,collide elastically and bounce back after the collision.If the two originally had velocities that were equal in size but opposite in direction,then which one will be moving faster after the collision?

A machine gun is attached to a railroad flatcar that rolls with negligible friction.If the railroad car has a mass of 6.35 × 10⁴ kg,how many bullets of mass 35.0 g would have to be fired at 200 m/s off the back to give the railroad car a forward velocity of 0.56 m/s?

A model car is propelled by a cylinder of carbon dioxide gas.The cylinder emits gas at a rate of 5.00 g/s with an exit speed of 80.0 m/s.The car has a mass of 455 g,including the CO₂ cylinder.Starting from rest,what is the car's initial acceleration?

The units of impulse are equivalent to:

A 1 500-kg experimental rocket sled at rest on level frictionless rails is loaded with 55.0 kg of propellant.It exhausts the propellant in a 20-s "burn." The rocket moves at 155 m/s after the burn.What average force is experienced by the rocket during the burn?

The law of conservation of momentum is applicable to systems made up of objects described by which of the following?

Exam 6: Momentum, Impulse, and Collisions

A baseball infielder,mass 78.0 kg,jumps up with velocity 3.50 m/s and catches a 0.195-kg baseball moving horizontally at 55.0 m/s.Of the following,which is closest to the final momentum of the system,infielder and baseball?

A man standing on frictionless ice throws a 1.00-kg mass at 29.0 m/s at an angle of elevation of 50.0°.What was the magnitude of the man's momentum immediately after throwing the mass?

The kinetic energy of an object is quadrupled.Its momentum will change by what factor?

In a two-body collision,if the kinetic energy of the system is conserved,then which of the following best describes the momentum after the collision?

Neglecting gravity,doubling the exhaust velocity from a single stage rocket initially at rest changes the final kinetic energy of the burnout stage by what factor? Assume all other variables,such as the mass of the rocket and the mass of the fuel,do not change.

In an automobile collision,how does an airbag lessen the blow to the passenger? Assume as a result of the collision,the passenger stops.

The dimensional equivalence of the quantity "momentum" in terms of the fundamental quantities (mass,length,time) is:

An object of mass m moving at speed v0 strikes an object of mass 2m which had been at rest.The first object bounces backward along its initial path at speed v0.Is this collision elastic,and if not,what is the change in kinetic energy of the system?

A ball with original momentum +7.0 kg⋅m/s hits a wall and bounces straight back without losing any kinetic energy.The change in momentum of the ball is:

An unfueled 1000-kg experimental rocket sled at rest on level frictionless rails is loaded with 50 kg of propellant.It exhausts the propellant in a 20 s "burn." The rocket moves at 160 m/s after the burn.What average force is experienced by the rocket during the burn?

Two particles collide,one of them initially being at rest.Is it possible for both particles to be at rest after the collision?

Two masses m1 and m2,with m1 < m2,have momenta with equal magnitudes.How do their kinetic energies compare?

Two objects,one less massive than the other,collide elastically and bounce back after the collision.If the two originally had velocities that were equal in size but opposite in direction,then which one will be moving faster after the collision?

A machine gun is attached to a railroad flatcar that rolls with negligible friction.If the railroad car has a mass of 6.35 × 104 kg,how many bullets of mass 35.0 g would have to be fired at 200 m/s off the back to give the railroad car a forward velocity of 0.56 m/s?

A model car is propelled by a cylinder of carbon dioxide gas.The cylinder emits gas at a rate of 5.00 g/s with an exit speed of 80.0 m/s.The car has a mass of 455 g,including the CO2 cylinder.Starting from rest,what is the car's initial acceleration?

The units of impulse are equivalent to:

A 1 500-kg experimental rocket sled at rest on level frictionless rails is loaded with 55.0 kg of propellant.It exhausts the propellant in a 20-s "burn." The rocket moves at 155 m/s after the burn.What average force is experienced by the rocket during the burn?

The law of conservation of momentum is applicable to systems made up of objects described by which of the following?

An object of mass m moving at speed v₀ strikes an object of mass 2m which had been at rest.The first object bounces backward along its initial path at speed v₀.Is this collision elastic,and if not,what is the change in kinetic energy of the system?

Two masses m₁ and m₂,with m₁ < m₂,have momenta with equal magnitudes.How do their kinetic energies compare?

A machine gun is attached to a railroad flatcar that rolls with negligible friction.If the railroad car has a mass of 6.35 × 10⁴ kg,how many bullets of mass 35.0 g would have to be fired at 200 m/s off the back to give the railroad car a forward velocity of 0.56 m/s?

A model car is propelled by a cylinder of carbon dioxide gas.The cylinder emits gas at a rate of 5.00 g/s with an exit speed of 80.0 m/s.The car has a mass of 455 g,including the CO₂ cylinder.Starting from rest,what is the car's initial acceleration?