AP physics final exam review

The sum of two vectors of fixed magnitudes has the greatest magnitude when the angle between these two vectors is

0 degrees

A truck is using a hook a tow a car whose mass is one quarter that of a truck. If the force exerted by the truck on the car is 6000 N then the force exerted by the car on the truck is

6000 N

A stone is held at a height H above the ground. A second stone with four times the mass of the first one is held at the same height . The gravitational potential energy of the second stone compared to that of the first stone is: A) four times as much B) one fourth as much C) twice as much D) one half as much E) the same

A) four times as much

Which requires more work, increasing a cars speed from 0mph to 30 mph or from 50 mph to 60 mph? A) 0 to 30 mph B) 50 to 60 mph C) the same

B) 50 to 60 mph

You slam on the brakes of your car in a panic, and skid a certain distance on a straight level road. If you had been traveling twice as fast, what distance would the car have skidded, under the same conditions? A) It would have skidded twice as far B) It would have skidded 4 times farther C) It would have skidded one half as far D)It would have skidded 1.4 times as far E) It is impossible to tell from the info given

B) It would have skidded 4 times farther

which one has a higher kinetic energy: a 500kg object moving at 40 m/s or a 1000kg object moving at 20 m/s? A) the 1000 kg object B) the 500kg object C) both have the same

B) the 500kg object

A pilot drops a package from a plane flying horizontally at a constant speed. Neglecting air resistance when the package hits the ground the horizontal location of the plane will

Be directly over the package

Two frisky otters slide down a frictionless hillsides of the same height but different slopes. The slope of the hill of otter 1 is 30 degrees, while the slope of the other otter 2 is 60 degrees. If both start from rest, which otter is moving faster when she reaches the bottom of her hill

Both otters have the same speed at the bottom

Mary and Debra stand on a snow covered roof. They both throw snowballs with the same initial speed, but in different directions. Mary throws her snowball downward, at 30 degrees below the horizontal. Debra throws her snowball upward, at 30 degrees above the horizontal. What is true about just as the snowballs reach the ground below...

Both snowballs will hit the ground with the same speed AND marys snowball reaches the ground before Debras snowball

A 4 kg object is moving with speed 2 m/s. A 1kg object is moving with speed of 4 m/s. Both objects encounter the same constant braking force, and are brought to rest. Which object travels the greater distance before stopping? A) the 4kg object B) the 1kg object C) both objects travel the same distance D) Cannot be determined

C) Both objects travel the same distance

If the force on an object is in the negative direction, the work it does on the object must be:: A) Positive B) Negative C) The work could be either positive or negative, depending on the direction it moves

C) The work could be either positive or negative, depending on the direction it moves

Person X pushes twice as hard against a stationary brick wall as person Y. Which one of the following statements is correct? A) Both do positive work, but person X does four times the work of person Y B) Both do positive work, but person X does twice the work of person Y C) Both do zero work D) both do positive work, but person X does one-half the work of person Y E) Both do the same amount of positive work

C) both do zero work

When you drop a pebble from height H it reaches the ground with speed V if there is no air resistance. From what height should you drop it so it will reach the ground with twice speed? A) 2H B) 16 H C) square root of 2 D) 4H E) 8H

D) 4H

Two objects, one of mass M and the other of mass 2M are dropped from the top of a building. If there is no air resistance, when they hit the ground, A) the heavier one will have half the kinetic energy of the lighter one B) the heavier one will have four times the kinetic energy of the lighter one C) the heavier one will have one fourth the kinetic energy of the lighter one D) the heavier one will have twice the kinetic energy of the lighter one E) both will have the same kinetic energy

D) the heavier one will have twice the kinetic energy of the lighter one

A 35-N bucket of water is lifted vertically 3m and then returned to its original position. How much work did gravity do on the bucket during this process? A) 45 J B) 180 J C) 900 J D) 90 J E) 0 J

E) 0 J

You and your friend, who weighs the same as you, want to go to the top of the Eiffel Tower. Your friend takes the elevator straight up. You decide to walk up the spiral stairway, taking longer to do so. Compare the gravitational potential energy of you and your friend, after you both reach the top. A) Your friends gravitational potential energy is greater than yours because he got to the top faster B) it is impossible to tell since the distances are unknown C) your gravitational potential energy is greater D) impossible to tell since times are unknown E) Both of you have the same amount of gravitational potential energy at the top

E) Both of you have the same amount of gravitational potential energy at the top

Two men, Joel and Jerry, push against a car that has stalled, trying unsuccessfully to get it moving. Jerry stops after 10min, while Joel is able to push for 5min longer. Compare the work they do on the car. A) Joel does 75% more work than Jerry B) Joel does 25% more work than Jerry C) Jerry does 50% more work than Joel D) Joel does 50% more work than Jerry E) Neither of them does any work

E) Neither of them does any work

An object of weight W is in freefall close to the surface of Earth. The magnitude of the force that the object exerts on the earth is

Equal to W

A bucket is being lowered by a very tight rope with a constant downward velocity. The tension in the rope must be

Equal to the weight of the bucket

A box is placed on a table which rests on a floor. The box pushes on the table; the reaction force to the box's push on the table is the tables push on the floor

False

In a collision between a huge SUV and a small hybrid car, the SUV exerts a larger force on the hybrid than the hybrid exerts on the SUV

False

You pull on a crate with a rope. If the crate moves, the ropes pull on the crate must have been larger than the crates pull on the rope, but if the crate does not move, both of these pulls must have been equal

False

Jill does twice as much work as Jack does and in half the time. Jills. Power output is

Four times jacks power output

Joe and bill throw identical balls vertically upward. Joe throws his ball with an initial speed twice as high as bill. If there is no air resistance the maximum height of joes ball will be

Four times that of Bill's ball

An elevator suspended by vertical cable is moving downward but slowing down. The tension in the cable must be

Greater than the weight of the elevator

For general projectile motion with no air resistance; the horizontal component of a projectiles acceleration

Is always zero

A rock is thrown from the upper edge of a tall cliff at some angle above the horizontal. It reaches its highest point and starts falling down. Which of the following statements about the rocks motion are true just before it hits the ground?

Its horizontal velocity component is the same as it was just as it launched

For general projectile motion with no air resistance, the vertical component of a projectiles acceleration

Remains a non- zero constant

You are in a train traveling on a horizontal track and notice that a piece of luggage starts to slide directly toward the front of the train. From this observation, you can conclude that this train is

Slowing down

Bill and his daughter Susan are both standing on identical skateboards initially at rest. Bill weighs three times as much as Susan. Bill pushes horizontally on Susan's back, causing Susan to start moving away from Bill. Just after Bill stops pushing,

Susan and Bill are moving away from each other, and susans speed is three times that of Bill

Two cyclists who weigh the same have identical bicycles ride up the same mountain, both starting at the same time. Joe rides straight up a mountain, and bob rides up the longer road that has a lower grade. Joe gets to the top before Bob. Ignoring friction and wind resistance which one of the following statements is true

The amount of work done by joe is equal to the amount of work done by Bob, but the average power exerted by Joe is greater than that of Bob

A ball is thrown horizontally from the top of a tower at the same time instant that a stone is dropped vertically. Which object is traveling faster when it hits the level ground below if neither of them experiences any air resistance?

The ball

What is true about an object in two dimensional projectile motion with no air resistance?

The horizontal acceleration is always zero and the vertical acceleration is always non-zero constant downward

An object is moving with constant non zero velocity. Which of the following statements about it MUST be true

The net force on the object is zero

If you pound a feather with a hammer which one feels the greater force?

The size of the force is always exactly the same on both of them

James and John drive from an overhang into the lake below. James simply drops straight down from the edge. John takes a running start and jumps with an initial horizontal velocity of 25 m/s. If there is no air resistance, when they reach the lake below

The splashdown speed of john is larger than that of james

A person stands on the edge of a cliff. She throws three identical rocks with the same speed. Rock X is thrown vertically upward, rock Y is thrown horizontally, and rock Z is thrown vertically downward. If the ground at the base of the cliff is level, which rock hits the ground with the greatest speed if there is no air resistance?

They all hit the ground with the same speed

In an air-free chamber, a pebble is thrown horizontally and at the same instant a second pebble is dropped from the same height. Compare the times of fall of the two pebbles.

They hit at the same time

You drive 6 km at 50 km/h and then another 6 km at 90 km/h. Your average speed over the 12 km drive will be

less than 70