AP Physics midterm MC (no graphs)

You drop a 50g egg from the 5th story window where it lands on the ground below. Will the following changes (a. increase, b. decrease, c. cause no change) to the final velocity of the egg just before it hits the ground. 1. The mass of the egg is doubled 2. The egg is thrown with an initial downward velocity 3. The egg is dropped from the 10th story 4. The egg is dropped on the moon (g=1.63 m/s²) 5. The egg is thrown with an initial upward velocity

1. c 2. a 3. a 4. b 5. a

A force produces power P by doing work W in a time T. What power will be produced by a force that does six times as much work in half as much time?

12P

A 200N sled slides down a frictionless hillside that rises 37° above the horizontal. What is the magnitude of the force that the surface of the hill exerts on the sled?

160N

When you drop a pebble from height H, it reaches the ground with kinetic energy K if there is no air resistance. From what height should you drop it so it will reach the ground with twice as much kinetic energy?

2H

A tiger is running in a straight line. If we both double the mass and speed of the tiger, the magnitude of its momentum will increase by what factor?

4

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?

4H

A person who normally weighs 700N is riding in a rather swift elevator that is moving at a constant speed of 9.8 m/s². If the person is standing on a bathroom scale inside the elevator, what would the scale read?

700N

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

Be directly over the package

A car that has a mass of 1400kg stales (stops) and needs to be pushed into a parking lot. The coefficient of static friction between the pavement and the tires is 0.45 and coefficient of kinetic friction between the pavement and the tires is 0.3. If the following people are available to help you (the max force they can push is listed), which person (alone) will be able to get the car moving from a stop. (List all that apply) Tim=6000N Sue=4000N Bill=6220N Kim=6500N You=5420

Bill and Kim

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 GPE of you and your friend, after you both reach the top.

Both of you have the same GPE at the top

A heavy rock and a light rock are dropped from the same height and experience no significant air resistance as they fall. Which of the following statements about these rocks are correct?

Both rocks have the same speed when they reach a ground AND When they reach the ground, the heavier rock has more KE than the larger rock

Three cars (car L, car M, and car N) are moving with the same velocity, and slam on the brakes. The most massive car is car L, and the least massive is car N. Assuming all three cars have identical tires, for which car is the amount of work done by friction in stopping it the highest?

Car L

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° below the horizontal; Debra throws her snowball upward, at 30° above the horizontal. Which of the following statements are true about just before the snowballs reach the ground below?

Debra's snowball will stay in the air longer than Mary's snowball. AND Debra's snowball has exactly the same acceleration as Mary's snowball

A block of mass m sits if a rough inclined ramp that makes an angle that is 60° with the horizontal. What must be true about the normal force F on the block due to the ramp?

F=mgsin30

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

False

If the rockets of a spaceship in outer space (far from all gravity) suddenly lose power and go off, the spaceship will gradually slow to a stop.

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

In order to get an object moving, you must push harder on it than it pushes back on you.

False

A small car and a large SUV are at a stoplight. The car has a mass equal to half that of the SUV, and the SUV can produce a maximum accelerating force equal to twice that of the car. When the light turns green, both drivers push their accelerators to the floor at the same time. Which vehicle pulls ahead of the other vehicle after a few seconds?

It is a tie

A truck has four times the mass of a car and is moving with twice the speed of the car. If Kt and Kc refer to the kinetic energies of truck and car respectively, it is correct to say that

Kt=16Kc

The acceleration due to gravity is lower on the Moon than on Earth. Which one of the following statements is true about the mass and weight of an astronaut on the Moon's surface, compared to Earth?

Mass is the same, weight is less

A crate is sliding down an inclined ramp at a constant speed of 0.55 m/s. The vector sum of all the forces acting on this crate must point

None of the above choices

A spring toy is compressed 1.5 cm and it flies straight up and reaches a maximum height of 43 cm. How could you find the velocity it has just before it hits the table on its way back down.

Set the GPE the toy has at the top of its flight equal to its KE just before it hits the table on its way back down AND Set the initial EPE equal to its KE just before it hits the table on its way back down

A spring toy is compressed 1.5 cm and it flies straight up and reaches a maximum height of 43 cm. How could you find the spring constant?

Set the initial EPE the toy has equal to its KE just before it hits the table on its way back down. AND Set the initial EPE equal to the GPE that the toy has at the top of the flight

Bill and his daughter Susan are both standing on identical skateboards (with really good frictionless ball bearings), 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 Susan's speed is three times that of Bill.

A rubber ball bounces off of a wall with an initial speed v and reverses its direction so its speed is v right after the bounce. As a result of this bounce, which of the following quantities of the ball are conserved?

The KE of the ball

Two cyclists who weigh the same and have identical bicycles ride up the same mountain both starting at the same time. Joe rides straight up the 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 player kicks a soccer ball in a high arc toward the opponent's goal. At the highest point in its trajectory,

The ball's vertical acceleration points downward

A heavy dart and a light dart are launched horizontally on a frictionless table by identical ideal springs. Both springs were initially compressed by the same amount. Which of the following statements about these darts are correct?

The darts both have the same kinetic energy just as they move free of the spring. AND The lighter dart leaves the spring moving faster than the heavy dart AND Both darts had the same initial EPE

An object moving with a constant non-zero velocity. Which of the following statements must be true?

The net force on the object is zero.

A small car meshes with a large truck in a head-on collision. Which of the following statements concerning the magnitude of the momentum change during the collision is correct?

The small car and the truck experience the same magnitude and momentum change.

Two objects have masses m and 5m respectively. They both are placed side by side on a frictionless inclined ramp and allowed to slide down from rest without any air resistance. Which one of the following statements about these objects is correct?

The two objects reach the bottom of the ramp at exactly the same time

A car that has a mass of 1400kg stales (stops) and needs to be pushed into a parking lot. The coefficient of static friction between the pavement and the tires is 0.45 and coefficient of kinetic friction between the pavement and the tires is 0.3. If the following people are available to help you (the max force they can push is listed), which person (alone) will be able to help you keep the car moving once it has started to move. (List all that apply) Tim=6000N Sue=4000N Bill=6220N Kim=6500N You=5420

Tim, Bill, Kim, and You

A 10kg rock and a 20kg rock are dropped at the same time and experience no significant air resistance. If the 10kg rock falls with acceleration a, what is the "a" of the 20kg rock?

a

A ball is thrown horizontally from the top of a tower at the same instant that a stone is dropped vertically. a) Which object has the greatest Vy when it hits the level ground below if neither of them experience any air resistance? b) Which object has the greater VR (total combined velocity) when it hits the level ground below if neither of them experience any air resistance?

a) Both are the same b) The ball

A 75-N box rests on a perfectly smooth horizontal surface. The minimum force need to start the box moving is

any horizontal force greater than zero

You are standing on a skateboard, initially at rest. A friend throws a very heavy ball towards you. You have two choices about what to do with the ball: either catch the ball of deflect it back toward your friend with the same speed as it was originally thrown. Which choice should you make in order to maximize your speed on the skateboard?

deflect the ball back

In a game of pool, the white cube ball hits the #5 ball and stops, while the #5 ball moves away with the same velocity as the cube ball had originally. Both balls have the same mass. This type of collision is

elastic

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

equal to the weight of the bucket

Jill does twice as much work as Jack does in half the time. Jill's power output is

four times Jack's power output

The momentum of an isolated system is conserved

in both elastic and inelastic collisions

Two objects are dropped from a bridge, an interval of 1.0s apart. Air resistance is negligible. During the time that both objects continue to fall, their separation

increases

For general projectile motion with no air resistance, the horizontal component of a projectile's acceleration

is always zero

A person who normally weighs 700N is riding in an elevator that is moving upward but is slowing down at a steady rate. If this person is standing on a bathroom scale inside the elevator, what would the scale read?

less that 700N

For general projectile motion with no air resistance, the horizontal component of a projectile's velocity during its flight

remains a non-zero constant

For general projectile motion with no air resistance, the vertical component of a projectile's 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

A rubber ball and a lump of clay have equal mass. They are thrown with equal speed against a wall. The ball bounces back with nearly the same speed with which it hit. The clay sticks to the wall. Which one of these objects experiences greater momentum?

the ball

Two objects of different masses have momentum of equal, non-zero magnitude. Which object has more kinetic energy?

the lighter object

During World War I, Germany used a "Big Bertha" cannon to hurl shells into Paris 30 miles away. This gun also had a very long barrel. What was the reason for using a long barrel in these guns?

to allow the force of the expanding gases from the gunpowder to act for a longer time

If a car accelerates at a uniform 4.0m/s, how long will it take to reach a speed of 80km/hr, starting from rest? If you could only use on equation to solve this, which one would you choose?

v = v₀ + at

An astronaut on a strange new planet finds that she can jump to a height of 27m before she falls back down when her initial upward speed is 6.0m/s. What is the magnitude of the acceleration due to gravity on the planet? If you could choose only one equation to solve this problem which would you choose?

v² = v₀² + 2a(x-x₀)

A runner starts at rest and runs the 100m dash in 12.3s. What is her acceleration? If you could only use one equation to solve this problem, which of the following would you choose?

x = x₀ + v₀t + ½at²