PSSI: Chapter 3 Reading Check
Two billiard balls having the same mass roll toward each other, each moving at the same speed. What is the combined momentum of the two balls?
0 kg/m/s
A feather and a coin dropped in a vacuum fall with equal
Accelerations
Compared to a recoiling rifle, the bullet fired has a greater
Kinetic energy
An object that has potential energy may have this energy because of its
Location
A moving object on which no forces are acting will continue to move with constant
Momentum
If you push for an hour against a stationary wall, you do no work
On the wall
A cannon recoils from firing a cannonball. The speed of the cannon's recoil is small because the
Cannon has more mass than the ball
Bullets are fired from an airplane in the forward direction of motion. The momentum of the airplane will be
Decreased
An open freight car rolls friction-free along a horizontal track in a pouring rain that falls vertically. As water accumulates in the car, its speed
Decreases
Compared with the force that brings a small car to a stop, the force required to bring a heavy truck traveling at the same speed to a stop
Depends on the time involved
In bungee jumping, the change in a jumper's kinetic energy equals the average force of the bungee cord multiplied by the stretching
Distance
Whereas impulse involves the time that a force acts, work involves the
Distance that a force acts
A freight train rolls along a track with considerable momentum. If it rolls at the same speed but has twice as much mass, its momentum is
Doubled
An object at rest may have
Energy
The force that accelerates a rocket in outer space is exerted on the rocket by the
Exhaust gases
A car that travels twice as fast as another when braking to a stop will skid
Four times as far
Two identical arrows, one with twice the speed of the other, are fired into a hay bale. The faster arrow will penetrate
Four times as far as the slower arrow
A heavy truck and a small car rolling down a hill at the same speed are forced to stop in the same amount of time. Compared to the force that stops the car, the force needed to stop the truck is
Greater
Momentum is transferred to the ground when an apple falls on it. The momentum absorbed by the ground is
Greater than that of the apple only if the apple bounces
When a car is braked to a stop, its kinetic energy is transformed to
Heat
A bullet is fired from a gun. The speed of the bullet will be about the same as the speed of the recoiling gun
If the mass of the bullet equals the mass of the gun
A cannonball shot from a cannon with a long barrel will have a greater muzzle velocity because the cannonball receives a greater
Impulse
Padded dashboards in cars are safer in an accident than nonpadded ones because an occupant hitting the dash has
Increased time of impact and decreased impact force
If an object has kinetic energy, then it also must have
Momentum
What does an object have when moving that it doesn't have when at rest?
Momentum
A golf ball is thrown at and bounces backward from a massive bowling ball that is initially at rest. After the collision, compared to the golf ball, the bowling ball has more
Momentum, but less kinetic energy
An object that has kinetic energy must be
Moving
The impulse-momentum relationship is a direct result of
Newton's second law
The conservation of momentum is most closely related to
Newton's third law
A heavy and a light object released from the same height in a vacuum have equal - All of these - Energies - None of these - Momenta - Weights
None of these
Which requires the most amount of work on the brakes of a car?
Slowing down from 100 km/h to 70 km/h
Suppose a gun were made of a strong but very light material. Suppose also that the pellet is more massive than the gun itself. For such a weapon
The target would be safer than the shooter
The difference between impulse and impact force involves the
Time the force acts
Two identical arrows, one with twice the kinetic energy of the other, are fired into a hay bale. The faster arrow will penetrate
Twice as far as the slower arrow
An object is raised above the ground gaining a certain amount of potential energy. If the same object is raised twice as high, it gains
Twice as much potential energy
If you push an object twice as far while applying the same force, you do
Twice as much work
If you do work on an object in half the time, your power output is
Twice the usual power output
A heavy pile driver starting from rest falls on a pile with a force that depends on the
All of these
A karate expert executes a swift blow and severs a cement block with her bare hand. The magnitude is the same for the - All of these - None of these - Force on both the block and the expert's hand - Impulse on both the block and the expert's hand - Time of impact on both the block and the expert's hand
All of these
A karate expert executes a swift blow and severs a cement block with her bare hand. The magnitude is the same for the - All of these - Time of impact on both the block and the expert's hand - Force on both the block and the expert's hand - None of these - Impulse on both the block and the expert's hand
All of these
A karate expert executes a swift blow and severs a cement block with her bare hand. The magnitude is the same for the - Impulse of both the block and the expert's hand - Force on both the block and the expert's hand - None of these - All of these - Time of impact on both the block and the expert's hand
All of these
A moving object has - All of these - Velocity - Speed - Energy - Momentum
All of these
The force on an apple hitting the ground depends upon - The time of impact with the ground - Whether or not the apple bounces - The speed of the apple just before it hits - All of these
All of these
Strictly speaking, if any electrical device in your car is turned on (such as an air conditioner, headlights, or even a radio), more gasoline is burned by the engine. This statement is
Always true
You're driving down the highway and a bug spatters into your windshield. Which undergoes the greater change in momentum?
Both the same
