A machine gun is attached to a railroad flatcar that rolls with negligible friction.If the railroad car has a mass of 7 × 104 kg,how many bullets of mass 20 g would have to be fired at 200 m/s off the back to give the railroad car a forward velocity of 0.5 m/s?

A) 8.8 B) 0.11 C) 1,400 D) 8,750 E) 14 A) 8.8 B) 0.11 C) 1,400 D) 8,750 E) 14

Exam 6: Momentum and Collisions

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Two skaters,both of mass 74 kg,are on skates on a frictionless ice pond.One skater throws a 0.3-kg ball at 6 m/s to his friend,who catches it and throws it back at 6 m/s.When the first skater has caught the returned ball,what is the velocity of each of the two skaters?

(Multiple Choice)

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Question 21

A valid unit for momentum is which of the following?

(Multiple Choice)

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Question 22

A 5-kg object is moving to the right at 4 m/s and collides with a 4-kg object moving to the left at 5 m/s.The objects collide and stick together.After the collision,the combined object:

(Multiple Choice)

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Question 23

A 71-kg man is standing in a 25-kg boat.The man steps to the right thinking he is stepping out onto the dock.However,the following will actually happen (ignore the friction of the water or air on the boat or the man):

(Multiple Choice)

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Question 24

A 29-g bullet moving at 1,100 m/s is fired through a one-kg block of wood emerging at a speed of 150 m/s.If the block had been originally at rest and is free to move,what is its resulting speed?

(Multiple Choice)

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Question 25

A model rocket sits on the launch pad until its fuel is ignited,blasting the rocket upward.During the short time of blast-off,as the ignited fuel goes down,the rocket goes up because:

(Multiple Choice)

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Question 26

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?

(Multiple Choice)

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Question 27

A 15-kg object sitting at rest is struck elastically in a head-on collision with a 12-kg object initially moving at +3.0 m/s.Find the final velocity of the 15-kg object after the collision.

(Multiple Choice)

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Question 28

A machine gun is attached to a railroad flatcar that rolls with negligible friction.If the railroad car has a mass of 7 × 10⁴ kg,how many bullets of mass 20 g would have to be fired at 200 m/s off the back to give the railroad car a forward velocity of 0.5 m/s?

(Multiple Choice)

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Question 29

A crane drops a 0.25 kg steel ball onto a steel plate.The ball's speeds just before impact and after are 4.0 m/s and 3.7 m/s,respectively.If the ball is in contact with the plate for 0.025 s,what is the magnitude of the average force that the ball exerts on the plate during impact?

(Multiple Choice)

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Question 30

During a snowball fight two balls with masses of 0.6 and 0.4 kg,respectively,are thrown in such a manner that they meet head-on and combine to form a single mass.The magnitude of initial velocity for each is 15 m/s.What is the speed of the 1.0-kg mass immediately after collision?

(Multiple Choice)

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Question 31

A lump of clay is thrown at a wall.A rubber ball of identical mass is thrown with the same speed toward the same wall.Which statement is true?

(Multiple Choice)

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Question 32

A 0.10-kg ball is moving at 6 m/s when it is hit by a bat,causing it to reverse direction and have a speed of 12 m/s.What is the change in the magnitude of the momentum of the ball?

(Multiple Choice)

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Question 33

A billiard ball is moving in the x-direction at 25.0 cm/s and strikes another billiard ball moving in the y-direction at 45.0 cm/s.As a result of the collision,the first ball moves at 55.0 cm/s,and the second ball stops.In what final direction does the first ball move?

(Multiple Choice)

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Question 34

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

(Multiple Choice)

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(85)

Question 35

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?

(Multiple Choice)

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Question 36

A 90-kg halfback running north with a speed of 11 m/s is tackled by a 125-kg opponent running south at 5 m/s.The collision is perfectly inelastic.Compute the velocity of the two players just after the tackle.

(Multiple Choice)

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Question 37

A cannon of mass 1,300 kg fires a 12-kg shell with a velocity of 150 m/s at an angle of 45° above the horizontal.Find the recoil velocity of the cannon across the level ground.

(Multiple Choice)

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Question 38

A car wash nozzle directs a steady stream of water at 2.0 kg/s,with a speed of 30 m/s,against a car window.What force does the water exert on the glass? Assume the water does not splash back.

(Multiple Choice)

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Question 39

The dimensional equivalent of the quantity impulse in terms of the fundamental quantities (mass,length,time)is which of the following?

(Multiple Choice)

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Question 40

Showing 21 - 40 of 83

Exam 6: Momentum and Collisions

Two skaters,both of mass 74 kg,are on skates on a frictionless ice pond.One skater throws a 0.3-kg ball at 6 m/s to his friend,who catches it and throws it back at 6 m/s.When the first skater has caught the returned ball,what is the velocity of each of the two skaters?

A valid unit for momentum is which of the following?

A 5-kg object is moving to the right at 4 m/s and collides with a 4-kg object moving to the left at 5 m/s.The objects collide and stick together.After the collision,the combined object:

A 71-kg man is standing in a 25-kg boat.The man steps to the right thinking he is stepping out onto the dock.However,the following will actually happen (ignore the friction of the water or air on the boat or the man):

A 29-g bullet moving at 1,100 m/s is fired through a one-kg block of wood emerging at a speed of 150 m/s.If the block had been originally at rest and is free to move,what is its resulting speed?

A model rocket sits on the launch pad until its fuel is ignited,blasting the rocket upward.During the short time of blast-off,as the ignited fuel goes down,the rocket goes up because:

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 15-kg object sitting at rest is struck elastically in a head-on collision with a 12-kg object initially moving at +3.0 m/s.Find the final velocity of the 15-kg object 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 7 × 104 kg,how many bullets of mass 20 g would have to be fired at 200 m/s off the back to give the railroad car a forward velocity of 0.5 m/s?

A crane drops a 0.25 kg steel ball onto a steel plate.The ball's speeds just before impact and after are 4.0 m/s and 3.7 m/s,respectively.If the ball is in contact with the plate for 0.025 s,what is the magnitude of the average force that the ball exerts on the plate during impact?

During a snowball fight two balls with masses of 0.6 and 0.4 kg,respectively,are thrown in such a manner that they meet head-on and combine to form a single mass.The magnitude of initial velocity for each is 15 m/s.What is the speed of the 1.0-kg mass immediately after collision?

A lump of clay is thrown at a wall.A rubber ball of identical mass is thrown with the same speed toward the same wall.Which statement is true?

A 0.10-kg ball is moving at 6 m/s when it is hit by a bat,causing it to reverse direction and have a speed of 12 m/s.What is the change in the magnitude of the momentum of the ball?

A billiard ball is moving in the x-direction at 25.0 cm/s and strikes another billiard ball moving in the y-direction at 45.0 cm/s.As a result of the collision,the first ball moves at 55.0 cm/s,and the second ball stops.In what final direction does the first ball move?

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

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 90-kg halfback running north with a speed of 11 m/s is tackled by a 125-kg opponent running south at 5 m/s.The collision is perfectly inelastic.Compute the velocity of the two players just after the tackle.

A cannon of mass 1,300 kg fires a 12-kg shell with a velocity of 150 m/s at an angle of 45° above the horizontal.Find the recoil velocity of the cannon across the level ground.

A car wash nozzle directs a steady stream of water at 2.0 kg/s,with a speed of 30 m/s,against a car window.What force does the water exert on the glass? Assume the water does not splash back.

The dimensional equivalent of the quantity impulse in terms of the fundamental quantities (mass,length,time)is which of the following?

Introduction

Introduction: Part A

Motion in One Dimension

Motion in One Dimension: Part A

Vectors and Two-Dimensional Motion

Vectors and Two-Dimensional Motion: Part A

The Laws of Motion

The Laws of Motion: Part A

Energy

Energy: Part A

Momentum and Collisions: Part A

Rotational Motion and the Law of Gravity

Rotational Motion and the Law of Gravity: Part A

Rotational Equilibrium and Rotational Dynamics

Rotational Equilibrium and Rotational Dynamics: Part A

Solids and Fluids

Solids and Fluids: Part A

Thermal Physics

Thermal Physics: Part A

Energy in Thermal Processes Heat and Internal Energy

Energy in Thermal Processes Heat and Internal Energy: Part A

The Laws of Thermodynamics Work in Thermodynamic Processes

The Laws of Thermodynamics Work in Thermodynamic Processes: Part A

Vibrations and Waves

Vibrations and Waves: Part A

Sound

Sound: Part A

Electric Forces and Electric Fields

Electric Forces and Electric Fields: Part A

Electrical Energy and Capacitance

Electrical Energy and Capacitance: Part A

Current and Resistance Electric Current

Current and Resistance Electric Current: Part A

Direct-Current Circuits Sources of EMF

Direct-Current Circuits Sources of EMF: Part A

Magnetism Magnets

Magnetism Magnets: Part A

Induced Voltages and Inductance

Induced Voltages and Inductance: Part A

Alternating-Current Circuits and Electromagnetic Waves

Alternating-Current Circuits and Electromagnetic Waves: Part A

Reflection and Refraction of Light

Reflection and Refraction of Light: Part A

Mirrors and Lenses

Mirrors and Lenses: Part A

Wave Optics

Wave Optics: Part A

Optical Instruments

Optical Instruments: Part A

Relativity

Relativity: Part A

Quantum Physics Blackbody Radiation and Plancks Hypothesis

Quantum Physics Blackbody Radiation and Plancks Hypothesis: Part A

Atomic Physics

Atomic Physics: Part A

Nuclear Physics

Nuclear Physics: Part A

Nuclear Energy and Elementary Particles

Nuclear Energy and Elementary Particles: Part A

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 machine gun is attached to a railroad flatcar that rolls with negligible friction.If the railroad car has a mass of 7 × 10⁴ kg,how many bullets of mass 20 g would have to be fired at 200 m/s off the back to give the railroad car a forward velocity of 0.5 m/s?