Transcript Review

Momentum
Which object has the greatest momentum?
(A) a 5.00-kg mass moving at 10.0 m/s
(B) a 10.0-kg mass moving at 1.00 m/s
(C) a 15.0-kg mass moving at 10.0 m/s
(D) a 20.0-kg mass moving at 1.00 m/s
What is the speed of a 1.0×103-kg car that has
a momentum of 2.0×104 kg•m/ s east?
(A) 5.0 × 10–2 m/s
(B) 2.0 × 101 m/s
(C) 1.0 × 104 m/s
(D) 2.0 × 107 m/s
Cart A has a mass of 2 kg and speed of 3 m/s. Cart
B has a mass of 3 kg and speed of 2 m/s.
Compared to the inertia and magnitude of
momentum of cart A, cart B has
(A) the same inertia and a smaller magnitude
of momentum
(B) the same inertia and the same magnitude
of momentum
(C) greater inertia and a smaller magnitude of
momentum
(D) greater inertia and the same magnitude of
momentum
Impulse
Which two quantities can be expressed using
the same units?
(A) energy and force
(B) impulse and force
(C) momentum and energy
(D) impulse and momentum
A 60-kg rollerskater exerts a 10-N force on a
30-kg rollerskater for 0.20 second. What is
the magnitude of the impulse applied to the
30-kg rollerskater?
(A) 50 N•s
(B) 2.0 N•s
(C) 6.0 N•s
(D) 12 N•s
A 0.149-kilogram baseball, initially moving at
15 meters per second, is brought to rest in
0.040 second by a baseball glove on a
catcher’s hand. The magnitude of the average
force exerted on the ball by the glove is
(A) 2.2 N
(B) 2.9 N
(C) 17 N
(D) 56 N
Which situation will produce the greatest
change of momentum for a 1.0-kilogram cart?
(A) accelerating it from rest to 3.0 m/s
(B) accelerating it from 2.0 m/s to 4.0 m/s
(C) applying a net force of 5.0 N for 2.0 s
(D) applying a net force of 10.0 N for 0.5 s
A 0.15-kilogram baseball moving at 20 m/s
is stopped by a catcher in 0.010 second. The
average force stopping the ball is
(A) 3.0×10–2 N
(B) 3.0×10 N
(C) 3.0×10 N
(D) 3.0×10 N
0
1
2
A 6.0-kilogram block, sliding to the east
across a horizontal, frictionless surface with a
momentum of 30 kg•m /s, strikes an obstacle.
The obstacle exerts an impulse of 10 N•s to
the west on the block. The speed of the block
after the collision is
(A) 1.7 m/s
(C) 5.0 m/s
(B) 3.3 m/s
(D) 20. m/s
A force of 6.0 newtons changes the
momentum of a moving object by 3.0
kilogram•meters per second. How long did
the force act on the mass?
(A) 1.0 s
(B) 2.0 s
(C) 0.25 s
(D) 0.50 s
A 60-kilogram student jumps down from a
laboratory counter. At the instant he lands on
the floor his speed is 3 meters per second. If
the student stops in 0.2 second, what is the
average force of the floor on the student?
(1) 1×10–2 N
(3) 9×102 N
2
(2) 1×10 N
(4) 4N
A 2.0-kg laboratory cart is sliding across a
horizontal frictionless surface at a constant
velocity of 4.0 m/s east. What will be the
cart’s velocity after a 6.0-Newton westward
force acts on it for 2.0 seconds?
(A) 2.0 m/s east
(B) 10 m/s east
(C) 2.0 m/s west
(D) 10 m/s west
A 1,200-kg car traveling at 10 m/s hits a tree
and is brought to rest in 0.10 second. What is
the magnitude of the average force acting on
the car to bring it to rest?
(1) 1.2×102 N
(2) 1.2×103 N
4
(3) 1.2×10 N
5
(4) 1.2×10 N
A 50-kg student threw a 0.40-kg ball with a
speed of 20 m/s. What was the magnitude of
the impulse that the student exerted on the
ball?
(A) 8.0 N•s
(B) 78 N•s
2
(C) 4.0 × 10 N•s
(D) 1.0 × 103 N•s
A 2.0-kg body is initially traveling at a
velocity of 40 m/s east. If a constant force of
10 Newtons due east is applied to the body
for 5.0 seconds, the final speed of the body is
(A) 15 m/s
(B) 65 m/s
(C) 25 m/s
(D) 130 m/s
The instant before a batter hits a 0.14kilogram baseball, the velocity of the ball is
45 meters per second west. The instant after
the batter hits the ball, the ball’s velocity is 35
meters per second east. The bat and ball are in
contact for 1.0 × 10–2 second. Calculate the
initial momentum of the ball.
The instant before a batter hits a 0.14-kg
baseball, the velocity of the ball is 45 meters
per second west. The instant after the batter
hits the ball, the ball’s velocity is 35 meters
per second east. The bat and ball are in
contact for 1.0 × 10–2 second. Calculate the
magnitude of the average force the bat exerts
on the ball while they are in contact.
Calculate the magnitude of the impulse
applied to a 0.75-kilogram cart to change its
velocity from 0.50 meter per second east to
2.00 meters per second east.
A 1000-kilogram car traveling due
east at 15 meters per second is hit
from behind and receives a forward
impulse of 6000 Newton-seconds.
Determine the magnitude of the car’s
change in momentum due to this
impulse.
A motorcycle being driven on a dirt path hits a rock.
Its 60-kilogram cyclist is projected over the
handlebars at 20 meters per second into a haystack.
If the cyclist is brought to rest in 0.50 second, the
magnitude of the average force exerted on the
cyclist by the haystack is
(A) 6.0 × 101 N
(B) 5.9 × 102 N
(C) 1.2 × 103 N
(D) 2.4 × 103 N
Elastic
At the circus, a 100-kilogram clown is fired at
15 meters per second from a 500-kilogram
cannon. What is the recoil speed of the
cannon?
(A) 75 m/s
(B) 15 m/s
(C) 3.0 m/s
(D) 5.0 m/s
Ball A of mass 5.0 kg moving at 20 m/s
collides with ball B of unknown mass moving
at 10 m/s in the same direction. After the
collision, ball A moves at 10 m/s and ball B
at 15 m/s, both still in the same direction.
What is the mass of ball B?
(A) 6.0 kg
(B) 2.0 kg
(C) 10. kg
(D) 12 kg
A 1.2-kg block and a 1.8-kg block are initially
at rest on a frictionless, horizontal surface.
When a compressed spring between the blocks
is released, the 1.8-kg block moves to the right
at 2.0 m/s. What is the speed of the 1.2-kg
block after the spring is released?
(A) 1.4 m/s
(B) 2.0 m/s
(C) 3.0 m/s
(D) 3.6 m/s
Inelastic
A 1.0-kg laboratory cart moving with a velocity of
0.50 m/s due east collides with and sticks to a
similar cart initially at rest. After the collision, the
two carts move off together with a velocity of 0.25
m/s due east. The total momentum of this
frictionless system is
(A) zero before the collision
(B) zero after the collision
(C) the same before and after the collision
(D) greater before the collision than after the
collision
A 3.0-kg steel block is at rest on a friction-less
horizontal surface. A 1.0-kg lump of clay is
propelled horizontally at 6.0 m/s toward the
block. Upon collision, the clay and steel block
stick together and move to the right with a
speed of
(A) 1.5 m/s
(B) 3.0 m/s
(C) 6.0 m/s
(D) 2.0 m/s
A 3.1-kilogram gun initially at rest is free to
move. When a 0.015-kilogram bullet leaves
the gun with a speed of 500 m/s, what is the
speed of the gun?
(A) 0.0 m/s
(B) 2.4 m/s
(C) 7.5 m/s
(D) 500 m/s
A woman with horizontal velocity v1 jumps
off a dock into a stationary boat. After landing
in the boat, the woman and the boat move
with velocity v2. Compared to velocity v1,
velocity v2 has
(A) the same magnitude and the same
direction
(B) the same magnitude and opposite
direction
(C) smaller magnitude and the same direction
(D) larger magnitude and the same direction
At the circus, a 100-kg clown is fired at 15
m/s from a 500-kg cannon. What is the recoil
speed of the cannon?
(A) 75 m/s
(B) 3.0 m/s
(C) 15 m/s
(D) 5.0 m/s
An 8.00-kilogram ball is fired horizontally
from a 1.00 × 103-kg cannon initially at rest.
After having been fired, the momentum of
the ball is 2.40 × 103 kg•m/s east.
Calculate the magnitude of the cannon’s
velocity after the ball is fired.
A 50-kilogram child running at 6.0 meters per
second jumps onto a stationary 10-kilogram
sled. The sled is on a level frictionless surface.
Calculate the speed of the sled with the child
after she jumps onto the sled.
A 1200-kilogram car moving at 12 meters per
second collides with a 2300-kilogram car that
is waiting at rest at a traffic light. After the
collision, the cars lock together and slide.
Eventually, the combined cars are brought to
rest by a force of kinetic friction as the rubber
tires slide across the dry, level, asphalt road
surface.
Calculate the speed of the locked-together
cars immediately after the collision.