Chapter 3 Quizzes
A job is done slowly, while an identical job is done quickly. Both jobs require the same amount of work, but different amounts of
power
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
Exert 1 N for a distance of 1 m in 1 s and you deliver a power of
1 W
A piece of putty moving with 1 unit of momentum strikes and sticks to a heavy bowling ball that is initially at rest. After the putty sticks to the ball, both move with a combined momentum of
1 unit
A 2-kg mass has 40 J of potential energy with respect to the ground. Approximately how far is it located above the ground
2 m
A 2-kg mass has 40 J of potential energy with respect to the ground. Approximately how far is it located above the ground?
2 m
A bow is drawn so that it has 40 J of potential energy. When fired, the arrow will ideally have a kinetic energy of
40 J
A 2-kg mass is held 4 m above the ground. What is the approximate potential energy of the mass with respect to the ground
80 J
The impulse-momentum relationship is a direct result of
Newton's second law
The impulse-momentum relationship is a direct result of
Newton's second law.
When you jump from an elevated position you usually bend your knees upon reaching the ground. By doing this, the time of the impact is about 10 times more than for a stiff-legged landing. In this way the average force your body experiences is reduced by
about 10 times
A heavy pile driver starting from rest falls on a pile with a force that depends on the (distance the pile falls, original height of the driver, original potential energy of the driver, all of these, none of these)
all of these
If the speed of a moving object doubles, then what else doubles
momentum
The power expended with a barbell is raised 2.0 m in 2 s is
dependent on the mass of the barbell
In bungee jumping, the change in a jumper's kinetic energy equals the average force of the bungee cord multiplied by the stretching
distance
The reason a bullet has more kinetic energy than the recoiling rifle from which it is fired is because the force on the bullet acts over a longer
distance
An object at rest may have
energy
When a car is braked to a stop, its kinetic energy is transformed to
heat
According to the impulse-momentum equation Ft = change in (mv), a bungee jumper in fall has momentum which is reduced by the force F exerted by the bungee cord. If m is the mass of the jumper, then v in the equation is the speed of the
jumper
Compared to a recoiling rifle, the bullet fired has a greater
kinetic energy
A clerk can lift containers a vertical distance of 1 m or can roll them up a 2-m-long ramp to the same elevation. With the ramp, the applied force required is
less.
A heavy truck and a small truck roll down a hill. Neglecting friction, at the bottom of the hill, the heavy truck will have greater
momentum
If an object has kinetic energy, then it also must have
momentum
No work is done by gravity on a bowling ball that rolls along a bowling alley because
the force on the ball is at right angles to the ball's motion.
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
true only if the car's engine is running
A bungee jumper makes her jump. The force of the bungee cord on her is greatest when her
velocity is minimum
Recoil is noticeable if we throw a heavy ball while standing on roller skates. If instead we go through the motions of throwing the ball but hold onto it, our net recoil will be
zero.
A 2-kg mass is held 4 m above the ground. What is the approximate potential energy of the mass with respect to the ground?
80 J
When a rifle is fired, it recoils so both the bullet and rifle are set in motion. The rifle and bullet ideally acquire equal (but opposite amounts of momentum, amounts of kinetic energy, both of these, none of these)
but opposite amounts of momentum
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.
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
Two objects, A and B, have the same size and shape, but A is twice as heavy as B. When they are dropped simultaneously from a tower, they reach the ground at the same time, but A has greater
momentum.
A 1000-kg car and a 2000-kg car are hoisted the same distance in a gas station. Raising the more massive car requires
more than four times as much work.
An object that has kinetic energy must be
moving
If you push for an hour against a stationary wall, you do no work
on the wall
If you push an object twice as far while applying the same force, you do
twice as much work
When an object is lifted 10 m, it gains a certain amount of potential energy. If the same object is lifted 20 m, its potential energy gain is
twice as much.
If you do work on an object in half the time, your power output is
twice the usual power output