Concepts Of Physics: Final Exam (All Tests Put Together)
A diver who weighs 500 N steps off a diving board that is 10 m above the water. The diver hits the water with kinetic energy of
5,000 J.
Using 1000 J of work, a toy elevator is raised from the ground floor to the second floor in 20 seconds. The power needed to do this job was
50 W.
A person is attracted toward the center of Earth by a 500-N gravitational force. The Earth is attracted toward the person with a force of
500 N.
A vehicle that weighs 400 N on the surface of the Earth is traveling in outer space at a speed of 400 m/s . It can be stopped by applying a constant force of 20 N for
800 seconds.
Calculate the work done when a 26-N force pushes a cart 3.5 m.
91 Joules
The power required to exert 1 N force, over a distance of 1 m in 1 second is
1 W.
A 1-kg chunk of putty moving at 1 m/s collides with and sticks to a 5-kg bowling ball initially at rest. The bowling ball and putty then move with a momentum of
1 kg m/s.
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 baseball player bats a ball with a force of 1000 N. The reaction force that the ball exerts against the bat is
1,000 N.
Joanne drives her car with a mass of 1000 kg at a speed of 19 m/s. Find a road friction force that is need to bring her car to a halt in 15 s. Express your answer to two significant figures and include the appropriate units.
1,300 N
A boxer punches a sheet of paper in midair and brings it from rest up to a speed of 30 m/s in 0.060 s . If the mass of the paper is 0.003 kg, what force does the boxer exert on it? Include units.
1.5 N
A vehicle that weighs 4000 N on the surface of the Earth is travelling in outer space at a speed of 200 m/s. The smallest constant force that must be applied to stop it in 20 seconds is
4000 N.
If you stand next to a wall on a frictionless skateboard and push the wall with a force of 42 N , how hard does the wall push on you? Express your answer to two significant figures and include the appropriate units.
42 N
A car that travels twice as fast as another when braking to a stop will skid
four times as far.
As a ball falls, the action force is the pull of Earth on the ball. The reaction force is the
pull of the ball's mass on the Earth.
A rifle recoils while firing a bullet. The speed of the rifle's recoil is small because the
rifle has much more mass than the bullet
A torque acting on an object tends to produce
rotation.
Which requires the most amount of work by the brakes of a car?
slowing down from 100 km/h to 70 km/h
Since each rolling wheel of a railroad train is tapered, the narrow part of the wheel has a tangential speed that is
smaller than that of the wide part.
Compared to falling on a stone floor, a wine glass may not break when it falls on a carpeted floor because the
stopping time is longer on the carpet.
The rotational inertia of your leg is greater when your leg is
straight.
Which has greater kinetic energy, a car traveling at 30 km/hr or a car of half the mass traveling at 60 km/hr?
the 60 km/hr car
Earth pulls on the moon. Similarly the moon pulls on Earth, evidence that
these two pulls comprise an action-reaction pair.
If you do work on an object in one-third the usual time, your power output is
three times the usual power output.
A light aluminum ball and a heavy lead ball of the same size are allowed to roll down an incline. When they are halfway down the incline, they will have identical
*NONE OF THESE*: (Momentum, Inertias, Potential Energies, Kinetic Energies.)
Resultant of two vectors at right angles to each other: R= Square Root (X^2+Y^2) Calculate the resultant of the pair of velocities 130 km/hr north and 80 km/hr west. Include Units
150 km/hr
A ball is moving at 3 m/s and has a momentum of 48 kg m/s. What is the ball's mass?
16 kg
A car moves 4 times as fast as another identical car. Compared to the slower car, the faster car has
16 times the KE (Kinetic Energy)
Do 100 J of work in 50s and your power output is
2 W.
Suppose the circumference of a bicycle wheel is 2 meters. If it rotates at 1 revolution per second when you are riding the bicycle, then your speed will be
2 m/s.
A car carrying a 79-kg test dummy crashes into a wall at 32 m/s and is brought to rest in 0.10 s. Find the average force exerted by the seat belt on the dummy. Express your answer to two significant figures and include the appropriate units.
25,000 N
A 2500-N pile-driver ram falls 10 m and drives a post 0.1 m into the ground. The average impact force on the ram is
250,000 N
A 4 kg ball has a momentum of 12 kg m/s. What is the ball's speed?
3 m/s.
A karate chop delivers a blow of 3000 N to a board that breaks. The force that acts on the hand during this event is
3,000 N
A 4.8-kg fish swimming 0.70 m/s swallows an absentminded 1.0-kg fish swimming toward it at a speed that brings both fish to a halt immediately after lunch. Find the speed of the approaching smaller fish before lunch. Express your answer to two significant figures and include the appropriate units.
3.4 m/s.
How many Joules of energy are in one kilowatt-hour?
3.6 million
Two people, one twice as massive as the other, attempt a tug-of-war with 12 meters of massless rope on frictionless ice. After a brief time, they meet. The heavier person slides a distance of
4 m.
A railroad diesel engine weighs four times as much as a freight car. If the diesel engine coasts at 5.0 km/h into a freight car that is initially at rest, find the speed of the coupled cars. Express your answer to two significant figures and include the appropriate units.
4.0 km/h.
A TV set is pushed a distance of 2 m with a force of 20 N. How much work is done on the set?
40 J.
A bow is drawn so that it has 40 J of potential energy. When fired, the arrow will ideally have a kinetic energy that is
40 J.
A piece of rope is pulled by two people in a tug-of-war. Each pulls with 400 N of force. What is the tension in the rope?
400 N
500 N barbell is lifted 2.2 m above the floor. A) What is the gain of potential energy of the barbell when it is lifted to this height?
A) (500 N * 2.2 m) = 1,100 J.
A) How much work is done when you push a crate horizontally with 100 N across a 14-m factory floor? B) If the force of friction on the crate is a steady 70 N. Find the KE gained by the crate.
A) You do (F * d) = (100 N * 14 m) = 1,400 J of work. B) Because of friction, net work on the crate is less. KE = net work = net force distance = (100 N - 70 N)(14 m) = 420 J.
The tapered shape of the parts of the wheels that ride on railroad tracks allows opposite wheels to
A) in effect, vary their diameters B) travel at different linear speeds for the same rotational speed. Answer is C) C) Neither A nor B is correct.
A car traveling along the highway needs a certain amount of force exerted on it to stop it in a certain distance. More stopping force is required when the car has
ALL OF THESE: more momentum, less stopping distance, more mass.
What task requires the most work; lifting a 50-kg sack 2 meters or lifting a 25-kg sack 4 meters?
Both require the same amount of work.
When a train makes a curve, different parts of the wheel rims
cover a different distance in the same time.
When bullets are fired from an airplane in the forward direction, the momentum of the airplane will be
Decreased.
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
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.
A clerk can lift containers a vertical distance of 1 meter or can roll them up a 2 meter-long ramp to the same elevation. With the ramp, the applied force required is about
Half as much.
When an automobile is braked to a stop, its kinetic energy is transformed to
Heat.
An object may have potential energy because of its
Location.
Two objects have the same size and shape, but one is much heavier than the other. When they are dropped simultaneously from a tower, they reach the ground at the same time, but the heavier one has a greater
Momentum
An object that has kinetic energy must be
Moving.
The impulse-momentum relationship is a direct result of
Newton's 2nd law.
The conservation of momentum is most closely related to
Newton's 3rd law.
Belly-flop Bernie dives from atop a tall flagpole into a swimming pool below. His potential energy at the top is 13,000 J (relative to the surface of the pool). What is his kinetic energy when his potential energy reduces to 1,000 J?
PE + KE = Total E; KE = 13,000 J - 1,000 J = 12,000 J.
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.
The force exerted on the tires of a car to directly accelerate it along a road is exerted by the
Road
A 1000-kg car and a 2000-kg car are hoisted the same distance. Raising the more massive car requires
Twice as much work.
An object lifted 10 meters gains 200 J of potential energy. If the same object is lifted 20 meters, its potential energy gain is
Twice as much.
If an object is raised twice as high, its potential energy will be
Twice as much.
If you find that twice as much work is needed to perform a task but it takes twice as much time, the amount of power required is
Unchanged
A Mack truck and a Volkswagen traveling at the same speed have a head-on collision. The vehicle that undergoes the greatest change in velocity will be the
Volkswagen.
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
Which of the following has the largest momentum relative to the Earth's surface?
a pickup truck speeding along a highway
When you jump from an elevated position you usually bend your knees upon reaching the ground. By doing this, you make the time of the impact about 10 times as great as for a stiff-legged landing. In this way the average force your body experiences is
about 1/10 as great.
Your friend says that the heavyweight champion of the world cannot exert a force of 50 N on a piece of tissue paper with his best punch. The tissue paper is held in mid air - no wall, no tricks. You
agree that it can't be done.
An archer shoots an arrow. Consider the action force to be the bowstring against the arrow. The reaction to this force is the
arrow's push against the bowstring
A coin and a ring roll down an incline starting at the same time. The one to reach the bottom first will be the
coin.
Your pet hamster sits on a record player whose angular speed is constant. If he moves to a point twice as far from the center, then his linear speed
doubles
A bird sitting on the limb of a tree is moving about 30 km/s with respect to the sun. If the bird takes 1 second to drop down to a worm below, the worm would be 30 km downrange from the bird when it reached the ground. This faulty reasoning is best countered with Newton's
first law.
A player hits a ball with a bat. The action force is the impact of the bat against the ball. The reaction to this force is the
force that the ball exerts on the bat.
A player catches a ball. Consider the action force to be the impact of the ball against the player's glove. The reaction to this force is the
force the glove exerts on the ball.
A karate expert executes a swift blow and breaks a cement block with her bare hand. The magnitude of the force experienced by her hand is
identical to the force applied to the block.
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.
Padded dashboards in cars are safer in an accident than non-padded ones because an occupant hitting the dash has
increased time of impact.
For an action force, there must be a reaction force that
is exactly equal in magnitude
A ball is projected into the air with 100 J of kinetic energy which is transformed to gravitational potential energy at the top of its trajectory. When it returns to its original level after encountering air resistance, its kinetic energy is
less than 100 J.
When you are in the way of a fast-moving object and can't get out of its way, you will suffer a smaller force of impact if you decrease its momentum over a
long time.
Horses that move with the fastest linear speed on a merry-go-round are located
near the outside.
An industrial flywheel has a greater rotational inertia when most of its mass is
nearest the rim.
If you push for a half hour or a whole hour against a stationary wall
no work on the wall is done in either case.
A large heavy truck and a small baby carriage roll down a hill. Neglecting friction, at the bottom of the hill, the baby carriage will have a greater
none of these
A skydiver falls towards the Earth. The attraction of the Earth on the diver pulls the diver down. What is the reaction to this force?
none of these
A 1-N apple falls to the ground. The apple hits the ground with an impact force of about
not enough information given to say
Which moves faster in m/s on a merry-go-round: a horse on the inside or a horse on the outside near the outer rail?
outside horse
It is correct to say that impulse is equal to
the change in momentum it produces.
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.
The attraction of a person's body toward Earth is called weight. The reaction to this force is
the person's body pulling on the Earth.
After rolling halfway down an incline, a marble's kinetic energy is
the same as its potential energy.
A automobile and a baby carriage traveling at the same speed collide head-on. The impact force is
the same for both.
A car traveling at 100 km/hr strikes an unfortunate bug and splatters it. The force of impact is
the same for both.
The force on an apple hitting the ground depends upon
the speed of the apple just before it hits, the time of impact with the ground, whether or not the apple bounces.
Suppose that a tiny gun made of a strong but very light material fires a bullet that is more massive than the gun itself. For such a weapon
the target would be safer than the shooter.
The ball rolling down an incline has its maximum potential energy at
the top.
To catch a ball, a baseball player extends the hand forward before impact with the ball and then lets it ride backward in the direction of the ball's motion. Doing this reduces the force of impact on the player's hand principally because the
time of impact is increased.
If you push an object a given distance, while applying twice the force, you do
twice as much work.
If you push an object twice as far while applying the same force, you do
twice as much work.
