Question 1

If you know the impulse that has acted on a body of mass m you can calculate:

Accepted Answer

A) its initial velocity. 
B) its final velocity. 
C) its final momentum. 
D) the change in its velocity. 
E) its acceleration during the impulse. 
A) its initial velocity. 
B) its final velocity. 
C) its final momentum. 
D) the change in its velocity. 
E) its acceleration during the impulse.

Question 2

In an elastic collision between two bodies of mass m1 and m2, with m2 initially at rest, mass 1 moves off at angle $\theta$ relative to the direction of its initial velocity and mass 2 at angle$\phi$. An exam paper shows the equations below: m1v1i
0
= m1v1f cos$\theta$ + m2v2f sin$\phi$
= m1v1f sin$\theta$ + m2v2f cos$\phi$
What error(s) has the student made?

Accepted Answer

A) In the first equation, m2v2f sin$\phi$ should be m2v2f cos$\phi$. 
B) In the second equation, m2v2f cos$\phi$ should be m2v2f sin$\phi$. 
C) In the second equation, the plus sign between the terms on the right should be a minus sign. 
D) All of the errors listed above. 
E) Only errors (a) and (b) above. 
A) In the first equation, m2v2f sin$\phi$ should be m2v2f cos$\phi$. 
B) In the second equation, m2v2f cos$\phi$ should be m2v2f sin$\phi$. 
C) In the second equation, the plus sign between the terms on the right should be a minus sign. 
D) All of the errors listed above. 
E) Only errors (a) and (b) above.

Question 3

The linear density of a rod, in g/m, is given by $\lambda=40.0+30.0 x$ . The rod extends from the origin to x = 0.400 m. What is the mass of the rod?

Accepted Answer

A) 0.213 g 
B) 3.50 g 
C) 3.84 g 
D) 18.4 g 
E) 20.8 g 
A) 0.213 g 
B) 3.50 g 
C) 3.84 g 
D) 18.4 g 
E) 20.8 g

Question 4

A uniform thin wire has a length $L=\pi R$ and is bent into a semicircular arc of radius R. If the wire starts at (x, y) = (R, 0) and curves counterclockwise to (x, y) = (-R, 0), what is the y coordinate of its centre of mass?

Accepted Answer

The answer of A uniform thin wire has a length...

Question 5

A 3.0-kg object moving 8.0 m/s in the positive x direction has a one-dimensional elastic collision with an object (mass = M) initially at rest. After the collision the object of unknown mass has a velocity of 6.0 m/s in the positive x direction. What is M?

Accepted Answer

A) 7.5 kg 
B) 5.0 kg 
C) 6.0 kg 
D) 4.2 kg 
E) 8.0 kg 
A) 7.5 kg 
B) 5.0 kg 
C) 6.0 kg 
D) 4.2 kg 
E) 8.0 kg

Question 6

Two cars start at the same point, but travel in opposite directions on a circular path of radius R, each at speed v. While each car travels a distance less than $\frac{\pi}{2} \mathrm{R}$ , one quarter circle, the centre of mass of the two cars:

Accepted Answer

A) remains at the initial point. 
B) travels along a diameter of the circle at speed v'  v. 
E) remains at the centre of the circle. 
A) remains at the initial point. 
B) travels along a diameter of the circle at speed v'  v. 
E) remains at the centre of the circle.

Question 7

A 4.2-kg object, initially at rest, 'explodes' into three objects of equal mass. Two of these are determined to have velocities of equal magnitudes (5.0 m/s) with directions that differ by 90$\degree$. How much kinetic energy was released in the explosion?

Accepted Answer

A) 70 J 
B) 53 J 
C) 60 J 
D) 64 J 
E) 35 J 
A) 70 J 
B) 53 J 
C) 60 J 
D) 64 J 
E) 35 J

Question 8

A 4.0-kg mass has a velocity of 4.0 m/s east when it explodes into two 2.0-kg masses. After the explosion one of the masses has a velocity of 3.0 m/s at an angle of 60$\degree$north of east. What is the magnitude of the velocity of the other mass after the explosion?

Accepted Answer

A) 7.9 m/s 
B) 8.9 m/s 
C) 7.0 m/s 
D) 6.1 m/s 
E) 6.7 m/s 
A) 7.9 m/s 
B) 8.9 m/s 
C) 7.0 m/s 
D) 6.1 m/s 
E) 6.7 m/s

Question 9

A 10-g bullet moving horizontally with a speed of 2.0 km/s strikes and passes through a 4.0-kg block moving with a speed of 4.2 m/s in the opposite direction on a horizontal frictionless surface. If the block is brought to rest by the collision, what is the kinetic energy of the bullet as it emerges from the block?

Accepted Answer

A) 0.51 kJ 
B) 0.29 kJ 
C) 0.80 kJ 
D) 0.13 kJ 
E) 20 kJ 
A) 0.51 kJ 
B) 0.29 kJ 
C) 0.80 kJ 
D) 0.13 kJ 
E) 20 kJ

Question 10

A bowler claims he can throw a cricket ball with as much momentum as a 3.00-g bullet moving with a speed of 1500 m/s. A cricket ball has a mass of 0.145 kg. What must be its speed if the bowler's claim is valid?

Accepted Answer

The answer of A bowler claims he can throw a...

Question 11

A U-238 nucleus (mass = 238 units) decays, transforming into an alpha particle (mass = 4.00 units) and a residual thorium nucleus (mass = 234 units). If the uranium nucleus was at rest, and the alpha particle has a speed of 1.50 * 107 m/s, determine the recoil speed of the thorium nucleus.

Accepted Answer

The answer of A U-238 nucleus (mass = 238 units)...

Question 12

The linear density of a rod, in g/m, is given by $\lambda=40.0+30.0 x$ . The rod extends from the origin to x = 0.400 m. What is the location of the centre of mass of the rod?

Accepted Answer

A) x = 0.213 m 
B) x = 0.315 m 
C) x = 0.384 m 
D) x = 0.184 m 
E) x = 0.208 m 
A) x = 0.213 m 
B) x = 0.315 m 
C) x = 0.384 m 
D) x = 0.184 m 
E) x = 0.208 m

Question 13

High-speed stroboscopic photographs show that the head of a golf club of mass 200 grams is travelling at 55.0 m/s just before it strikes a 46.0-gram golf ball at rest on a tee. After the collision, the clubhead travels (in the same direction) at 40.0 m/s. Find the speed of the golf ball just after impact.

Accepted Answer

The answer of High-speed stroboscopic photographs show that the head...

Question 14

Two blocks with masses 2.0 kg and 3.0 kg are placed on a horizontal frictionless surface. A light spring is placed in a horizontal position between the blocks. The blocks are pushed together, compressing the spring, and then released from rest. After contact with the spring ends, the 3.0-kg mass has a speed of 2.0 m/s. How much potential energy was stored in the spring when the blocks were released?

Accepted Answer

A) 15 J 
B) 3.0 J 
C) 6.0 J 
D) 12 J 
E) 9.0 J 
A) 15 J 
B) 3.0 J 
C) 6.0 J 
D) 12 J 
E) 9.0 J

Question 15

Refer to Exhibit 8-1 below.Exhibit 8-1 Two birds of prey hurtling after the same rabbit collide in mid-air and grab each other with their talons. Each 250-g bird is flying at 30 m/s at a 60$\degree$angle to the ground.   What is the horizontal component of their momentum, in $\frac{\mathrm{kg} \cdot \mathrm{~m}}{\mathrm{~s}}$ , immediately after the collision?

Accepted Answer

A) 0 
B) 6.1 
C) 7.5 
D) 13 
E) 15 
A) 0 
B) 6.1 
C) 7.5 
D) 13 
E) 15

Question 16

A 3.00-kg stone is dropped from a 39.2 m high building. When the stone has fallen 19.6 m, the magnitude of the impulse the Earth has received from the gravitational force exerted by the stone is:

Accepted Answer

A) 9.80 N $\cdot$ s. 
B) 19.6 N $\cdot$ s. 
C) 29.4 N $\cdot$ s. 
D) 58.8 N $\cdot$ s. 
E) 118 N $\cdot$ s. 
A) 9.80 N $\cdot$ s. 
B) 19.6 N $\cdot$ s. 
C) 29.4 N $\cdot$ s. 
D) 58.8 N $\cdot$ s. 
E) 118 N $\cdot$ s.

Question 17

Refer to Exhibit 8-1 below.Exhibit 8-1 Two birds of prey hurtling after the same rabbit collide in mid-air and grab each other with their talons. Each 250-g bird is flying at 30 m/s at a 60$\degree$ angle to the ground.   What is the magnitude of their velocity, in m/s, immediately after the collision?

Accepted Answer

A) 0 
B) 13 
C) 15 
D) 26 
E) 30 
A) 0 
B) 13 
C) 15 
D) 26 
E) 30

Question 18

An astronaut outside a spaceship hammers a loose rivet back in place. What happens to the astronaut as he swings the hammer?

Accepted Answer

A) Nothing. The spaceship takes up the momentum of the hammer. 
B) He moves away from the spaceship. 
C) He moves towards the spaceship. 
D) He moves towards the spaceship as he pulls the hammer back and moves away from it as he swings the hammer forward. 
E) He moves away from the spaceship as he pulls the hammer back and moves toward it as he swings the hammer forward. 
A) Nothing. The spaceship takes up the momentum of the hammer. 
B) He moves away from the spaceship. 
C) He moves towards the spaceship. 
D) He moves towards the spaceship as he pulls the hammer back and moves away from it as he swings the hammer forward. 
E) He moves away from the spaceship as he pulls the hammer back and moves toward it as he swings the hammer forward.

Question 19

When two bodies of different masses collide, the impulses they exert on each other are:

Accepted Answer

A) equal for all collisions. 
B) equal but opposite for all collisions. 
C) equal but opposite only for elastic collisions. 
D) equal but opposite only for inelastic collisions. 
E) equal but opposite only when the bodies have equal but opposite accelerations. 
A) equal for all collisions. 
B) equal but opposite for all collisions. 
C) equal but opposite only for elastic collisions. 
D) equal but opposite only for inelastic collisions. 
E) equal but opposite only when the bodies have equal but opposite accelerations.

Question 20

A 1.6-kg block is attached to the end of a 2.0-m string to form a pendulum. The pendulum is released from rest when the string is horizontal. At the lowest point of its swing when it is moving horizontally, the block is hit by a 10-g bullet moving horizontally in the opposite direction. The bullet remains in the block and causes the block to come to rest at the low point of its swing. What was the magnitude of the bullet's velocity just before hitting the block?

Accepted Answer

A) 1.0 km/s 
B) 1.6 km/s 
C) 1.2 km/s 
D) 1.4 km/s 
E) 1.8 km/s 
A) 1.0 km/s 
B) 1.6 km/s 
C) 1.2 km/s 
D) 1.4 km/s 
E) 1.8 km/s

If you know the impulse that has acted on a body of mass m you can calculate:

The linear density of a rod, in g/m, is given by $\lambda=40.0+30.0 x$ . The rod extends from the origin to x = 0.400 m. What is the mass of the rod?

A uniform thin wire has a length $L=\pi R$ and is bent into a semicircular arc of radius R. If the wire starts at (x, y) = (R, 0) and curves counterclockwise to (x, y) = (-R, 0), what is the y coordinate of its centre of mass?

A 3.0-kg object moving 8.0 m/s in the positive x direction has a one-dimensional elastic collision with an object (mass = M) initially at rest. After the collision the object of unknown mass has a velocity of 6.0 m/s in the positive x direction. What is M?

Two cars start at the same point, but travel in opposite directions on a circular path of radius R, each at speed v. While each car travels a distance less than $\frac{\pi}{2} \mathrm{R}$ , one quarter circle, the centre of mass of the two cars:

A 4.2-kg object, initially at rest, 'explodes' into three objects of equal mass. Two of these are determined to have velocities of equal magnitudes (5.0 m/s) with directions that differ by 90 $\degree$ . How much kinetic energy was released in the explosion?

A 4.0-kg mass has a velocity of 4.0 m/s east when it explodes into two 2.0-kg masses. After the explosion one of the masses has a velocity of 3.0 m/s at an angle of 60 $\degree$ north of east. What is the magnitude of the velocity of the other mass after the explosion?

A bowler claims he can throw a cricket ball with as much momentum as a 3.00-g bullet moving with a speed of 1500 m/s. A cricket ball has a mass of 0.145 kg. What must be its speed if the bowler's claim is valid?

A U-238 nucleus (mass = 238 units) decays, transforming into an alpha particle (mass = 4.00 units) and a residual thorium nucleus (mass = 234 units). If the uranium nucleus was at rest, and the alpha particle has a speed of 1.50 * 107 m/s, determine the recoil speed of the thorium nucleus.

The linear density of a rod, in g/m, is given by $\lambda=40.0+30.0 x$ . The rod extends from the origin to x = 0.400 m. What is the location of the centre of mass of the rod?

A 3.00-kg stone is dropped from a 39.2 m high building. When the stone has fallen 19.6 m, the magnitude of the impulse the Earth has received from the gravitational force exerted by the stone is:

An astronaut outside a spaceship hammers a loose rivet back in place. What happens to the astronaut as he swings the hammer?

When two bodies of different masses collide, the impulses they exert on each other are:

Physics and Measurement

Motion in One Dimension

Motion in Two Dimensions

Forces and Newtons Laws

Further Applications of Newtons Laws

Work, Force and Energy

Conservation of Energy

Rotational Motion

Energy and Momentum in Rotating Systems

Gravity

Special Relativity

Fluid Statics

Fluid Dynamics

Solids

Oscillatory Motion

Wave Motion

Superposition and Interference

Heat and Temperature

Energy Transfer Processes and Thermodynamics

The Kinetic Theory of Gases

The Second Law of Thermodynamics, Heat Engines and Entropy

Filters

Exam 8: Linear Momentum and Collisions

If you know the impulse that has acted on a body of mass m you can calculate:

The linear density of a rod, in g/m, is given by λ=40.0+30.0x\lambda=40.0+30.0 xλ=40.0+30.0x . The rod extends from the origin to x = 0.400 m. What is the mass of the rod?

A uniform thin wire has a length L=πRL=\pi RL=πR and is bent into a semicircular arc of radius R. If the wire starts at (x, y) = (R, 0) and curves counterclockwise to (x, y) = (-R, 0), what is the y coordinate of its centre of mass?

A 3.0-kg object moving 8.0 m/s in the positive x direction has a one-dimensional elastic collision with an object (mass = M) initially at rest. After the collision the object of unknown mass has a velocity of 6.0 m/s in the positive x direction. What is M?

Two cars start at the same point, but travel in opposite directions on a circular path of radius R, each at speed v. While each car travels a distance less than π2R\frac{\pi}{2} \mathrm{R}2π​R , one quarter circle, the centre of mass of the two cars:

A 4.2-kg object, initially at rest, 'explodes' into three objects of equal mass. Two of these are determined to have velocities of equal magnitudes (5.0 m/s) with directions that differ by 90 °\degree° . How much kinetic energy was released in the explosion?

A 4.0-kg mass has a velocity of 4.0 m/s east when it explodes into two 2.0-kg masses. After the explosion one of the masses has a velocity of 3.0 m/s at an angle of 60 °\degree° north of east. What is the magnitude of the velocity of the other mass after the explosion?

A bowler claims he can throw a cricket ball with as much momentum as a 3.00-g bullet moving with a speed of 1500 m/s. A cricket ball has a mass of 0.145 kg. What must be its speed if the bowler's claim is valid?

A U-238 nucleus (mass = 238 units) decays, transforming into an alpha particle (mass = 4.00 units) and a residual thorium nucleus (mass = 234 units). If the uranium nucleus was at rest, and the alpha particle has a speed of 1.50 * 107 m/s, determine the recoil speed of the thorium nucleus.

The linear density of a rod, in g/m, is given by λ=40.0+30.0x\lambda=40.0+30.0 xλ=40.0+30.0x . The rod extends from the origin to x = 0.400 m. What is the location of the centre of mass of the rod?

A 3.00-kg stone is dropped from a 39.2 m high building. When the stone has fallen 19.6 m, the magnitude of the impulse the Earth has received from the gravitational force exerted by the stone is:

An astronaut outside a spaceship hammers a loose rivet back in place. What happens to the astronaut as he swings the hammer?

When two bodies of different masses collide, the impulses they exert on each other are:

Physics and Measurement

Motion in One Dimension

Motion in Two Dimensions

Forces and Newtons Laws

Further Applications of Newtons Laws

Work, Force and Energy

Conservation of Energy

Rotational Motion

Energy and Momentum in Rotating Systems

Gravity

Special Relativity

Fluid Statics

Fluid Dynamics

Solids

Oscillatory Motion

Wave Motion

Superposition and Interference

Heat and Temperature

Energy Transfer Processes and Thermodynamics

The Kinetic Theory of Gases

The Second Law of Thermodynamics, Heat Engines and Entropy

Filters

The linear density of a rod, in g/m, is given by $\lambda=40.0+30.0 x$ . The rod extends from the origin to x = 0.400 m. What is the mass of the rod?

A uniform thin wire has a length $L=\pi R$ and is bent into a semicircular arc of radius R. If the wire starts at (x, y) = (R, 0) and curves counterclockwise to (x, y) = (-R, 0), what is the y coordinate of its centre of mass?

Two cars start at the same point, but travel in opposite directions on a circular path of radius R, each at speed v. While each car travels a distance less than $\frac{\pi}{2} \mathrm{R}$ , one quarter circle, the centre of mass of the two cars:

A 4.2-kg object, initially at rest, 'explodes' into three objects of equal mass. Two of these are determined to have velocities of equal magnitudes (5.0 m/s) with directions that differ by 90 $\degree$ . How much kinetic energy was released in the explosion?

A 4.0-kg mass has a velocity of 4.0 m/s east when it explodes into two 2.0-kg masses. After the explosion one of the masses has a velocity of 3.0 m/s at an angle of 60 $\degree$ north of east. What is the magnitude of the velocity of the other mass after the explosion?

The linear density of a rod, in g/m, is given by $\lambda=40.0+30.0 x$ . The rod extends from the origin to x = 0.400 m. What is the location of the centre of mass of the rod?