AP Physics: Semester 2 Final

As a supersonic airplane increases its speed more and more, what happens the the half-angle of the conical shock wave?

decreases

As more resistors are added in a series to a constant voltage source, what happens to the power supplied by the source?

decreases

An object attached to an ideal spring executes simple harmonic motion. If you want to double its total energy, what could you do?

double the force constant (spring constant) of the spring

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

elastic

In an elastic collision involving an isolated system, what is the final total momentum?

exactly the same as the initial momentum

A simple harmonic oscillator oscillates with frequency f when its amplitude is A. If the amplitude is now doubled to 2A, what is the new frequency?

f

A sonic boom occurs only as an airplane just reaches the speed of sound in air, but not after it increases its speed. True or false?

false

True of false: there must be equal amounts of mass on both sides of the center of mass (or center of gravity) of a system?

false BECAUSE it must be equal all over

What happens to the force between two objects when one charge is doubled?

force vectors remain the same

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

four

If the angular frequency of the motion of a simple harmonic oscillator is doubled, by what factor does the maximum acceleration of the oscillator change?

four

If you want to double the momentum of a gas molecule, by what factor must you increase its kinetic energy?

four

As you are moving very quickly toward a speaker emitting a pure tone, which characteristics of the sound get larger?

frequency and loudness

A satellite encircles Mars at a distance above its surface equal to 3 times the radius of Mars. If gm is the acceleration due to gravity at the surface of Mars, what is the acceleration due to gravity at the location of the satellite?

gm/16

A railroad car collides with and sticks to an identical railroad car that is initially at rest. After the collision, what is the kinetic energy of the system?

half as much as before

A person sits on a freely spinning lab stool that has no friction in its axle. When this person extends her arms what happens to her moment of inertia and angular speed?

her moment of inertia increases and her angular speed decreases

As more resistors are added in parallel across a constant voltage source, what is the power supplied by the source?

increases

The length of a certain wire is doubled and at the same time its radius is also doubled. What is the new resistance of this wire?

it is 1/2 as large

The length of a certain wire is doubled and at the same time its radius is reduced by a factor of 2. What is the new resistance of this wire?

it is eight times as large

The length of a wire is kept same while its radius is doubled. What is the new resistance of this wire?

it is reduced by a factor of 4

Two friends are standing on opposite ends of a canoe that is initially at rest with respect to a frictionless lake. The person in the front throws a very massive ball toward the back, and the person in the back catches it. After the ball is caught, which direction does the canoe move?

it is stationary

The length of a certain wire is doubled while its radius is kept constant. What is the new resistance of this wire?

it is two times as large

Two point charges, Q1 and Q2, are separated by a distance R. If the magnitudes of both charges are doubled and their separation is also doubled, what happens to the electrical force that each charge exerts on the other one?

it remains the same

Two point charges, Q1 and Q2, are separated by a distance R. If the magnitudes of both charges are halved and their separation is also halved, what happens to the electrical force that each charge exerts on the other one?

it remains the same

In many cartoon shows, a character runs off a cliff, realizes his predicament, and lets out a scream. He continues to scream as he falls. If the physical situation is portrayed correctly, from the vantage point of an observer at the top of the cliff leaning over the edge, what should the pitch of the scream as he fall be?

lower than the original pitch and decreasing as he falls

Grandfather clocks are designed so they can be adjusted by moving the weight at the bottom of the pendulum up or down. Suppose you have a grandfather clock at home that runs fast. Which of the following adjustments of the weight would make it more accurate?

lower the weight

You are making a circular turn in your car on a horizontal road when you hit a big patch of ice, causing the force of friction between the tires and the road to become zero. While the car is on the ice, what is the direction of its path?

moves along a straight line path in its original direction

A very light ping-pong ball moving east at a speed of 4 m/s collides with a very heavy stationary bowling ball. Thing ping pong ball bounces back to the west, and the bowling ball moves very slowly to the east. Which object experiences the greater magnitude impulse during the collision?

neither, both experienced the same magnitude impulse

A negatively-charged plastic rod is brought close to (but does not touch) a neutral metal sphere that is connected to ground. After waiting a few seconds, the ground connection is removed (without touching the sphere), and after that the rod is also removed. What is the charge on the sphere?

neutral

Identical balls oscillate with the same period T on Earth. Ball A is attached to an ideal spring and ball B swings back and forth to form a simple pendulum. These systems are now taken to the Moon, where g = 1.6 m/s^2, and set into oscillation. What is true about which ball will take longer to complete a cycle and which will execute more vibrations each minute on the moon.

on the moon, ball B will take longer to complete one cycle than ball A but ball A will execute more vibrations each minute than ball B

You double your distance from a sound source that is radiating equally in all directions. What does the intensity of the sound reduce to?

one-fourth of its original value

An organ pipe of length L that is open at one end resonates in its third harmonic with a wavelength of 2L/3. Is the other end of the pipe closed or open?

open

What characteristics of a sound wave are related to the 'pitch' of a musical note?

period and wavelength

Grandfather clocks are designed so they can be adjusted by moving the weight at the bottom of the pendulum up or down. Suppose you have a grandfather clock at home that runs slow. Which of the following adjustments of the weight would make it more accurate?

raise the weight

A plastic rod is charged up by rubbing a wool cloth, and brought to an initially neutral metallic sphere that is insulated from ground. It is allowed to touch the sphere for a few seconds, and then is separated from the sphere by a small distance. After the rod is separated, what force does the rod feel by the sphere?

repelled by the sphere

What is current / potential?

resistance

A very elastic rubber ball is dropped from a certain height and hits the floor with a downward speed v. Since it is so elastic, the ball bounces back with the same speed v going upward. What is true about the magnitude of the balls momentum?

same before and after the bounce

A solid sphere, solid cylinder, and a hollow pipe all have equal masses and radii. If the three of them are released simultaneously at the top of an inclined plane and do not slip, which one will reach the bottom first?

sphere

Two uncharged metal spheres, #1 and #2, are mounted on insulating support rods. A third metal sphere, carrying a positive charge, is then placed near #2. Now a copper wire is momentarily connected between #1 and #2 and then removed. Finally, sphere #3 is removed. In this final state, what are the charges?

sphere #1 carries a positive charge and #2 carries negative charge

A disk, a hoop, and a solid sphere are released at the same time at the top of an inclined plane. They are all uniform and roll without slipping. In what order do they reach the bottom?

sphere, disk, hoop

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 the greater momentum change?

the ball

A 9V battery is hooked up to two resistors in series using wires of negligible resistance. One has a resistance of 5 ohms, and the other has a resistance of 10 ohms. Several locations along the circuit are marked with letters. What is true about the current and potential?

the current is exactly the same at all points, and the potential at B is equal to the potential at C.

A disk and a hoop of the same mass and radius are released at the same time at the top of an inclined plane. If both are uniform, which one reaches the bottom of the incline first if there is no slipping?

the disk

Four unequal resistors are connected in a parallel with each other. What is true about the equivalent resistance compared to the smaller resistor?

the equivalent resistance is less than that of the smallest resistor

Four unequal resistors are connected in series with each other. What is true about the resistors?

the equivalent resistance is more than than the largest resistance

Two equal-magnitude forces are applied to a door at the doorknob. The first force applied is perpendicular to the door, and the second force is applied at 30 degrees to the plane of the door. Which force exerts the greater torque about the door hinge?

the first force (applied perpendicular to the door)

Consider two less than desirable options. In the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. In the second option you are driving 30 mph and crash head-on into a stationary brick wall. In neither case does you car bounce back from the thing it hits, and the collision time is the same in both cases. Which of these two situations would result in the greater impact force on your car?

the force would be the same in both cases

What is Kirchhoff's junction rule a statement of?

the law of conservation of charge

A merry-go-round spins freely when Diego moves quickly to the center along a radius of a the merry-go-round. As he does this, what is true about the moment of inertia and his angular speed?

the moment of inertia of the system decreases and the angular speed increases

If we double the frequency of a system undergoing simple harmonic motion, what is true about the system?

the period is reduced to one-half of what it was and the angular frequency is doubled

Suppose a solid uniform sphere of mass M and radius R rolls without slipping down an inclined plane starting from rest. what does the angular velocity of the sphere at the bottom of the incline depend on?

the radius of the sphere

When unequal resistors are connected in a parallel circuit, what is the potential drop between each resistor?

the same

A rocket explodes into two fragments, one 25 times heavier than the other. What is the magnitude of momentum change of the lighter fragment?

the same as the momentum change of the heavier fragment

A small car meshes with a large truck in a head-on collision. What is true concerning the magnitude of the momentum change during the collision?

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

A small uniform disk and a small uniform sphere are released simultaneously at the top of a high inclined plane, and they roll down without slipping. Which one will reach the bottom first?

the sphere

A negatively-charged rod is brought close to (but does not touch) two neutral spheres that are in contact with each other but insulated from the ground. If the two spheres are then separated, what kind of charge will be on the spheres?

the sphere near the charged rod becomes positive and the other becomes negative

In a resonating pipe that is open at one end and closed at the other, where are antinodes/nodes?

there is a displacement node at the closed end and a displacement antinode at the open end

Three cars, car X, car Y, and car Z, begin accelerating from rest at the same time. Car X is more massive than car Y, which is more massive than car Z. The net accelerating force exerted on each car is identical. After 10 seconds, which car has the most amount of momentum?

they all have the same amount of momentum

An electron and a proton are released simultaneously from rest and start moving toward each other due to their electrostatic attraction, with no other forces present. What is true about their positioning before they are about to collide?

they are closer to the initial position of the proton than to the initial position of the electron

Consider the standing wave on a guitar string and the sound wave generated by the string as a result of this vibration. What do these two waves have in common?

they have the same period and frequency.

During WWI, 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 their guns?

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

If the answer to your calculation has units of kg x m^2/s^2, what type of quantity could it be?

torque, work, and rotational kinetic energy

When an object moves in uniform circular motion, what is the direction of its acceleration?

toward the center of its circular path

If the amplitude of the motion of a simple harmonic oscillator is doubled, by what factor does the maximum speed of the oscillator change?

two

A given force is applied to a rod in several different ways. In which case is the torque about the pivot P due to this force the greatest?

when it is completely perpendicular and on the corner of the rod

In simple harmonic motion, when is the magnitude of the acceleration the greatest?

when the kinetic energy is a minimum, and the magnitudes of the displacement and potential energy are at a maximum

In simple harmonic motion, when is the speed the greatest?

when the magnitude of the acceleration is a minimum and the potential energy is a zero

In a resonating pipe that is open at both ends, where are the displacement antinodes, if any?

each end

When a current flows through a metal wire, what are the moving charges?

only electrons

When a guitar is tuned to adjust pitch, what is it that is changed?

the frequency of the fundamental

What is resistance / potential?

1 / (current)

If Earth had twice its present mass but it orbited at the same distance from the sun as it does now, what would its orbital period be?

1 year

Two tuning forks have frequencies of 440 and 522 Hz. What is the best frequency if both are sounding simultaneously?

82 Hz

The lowest tone to resonate in pipe of length L that is open at both ends is 200 Hz. Which frequencies will not resonate in the same pipe?

900 Hz BECAUSE it does not divide into a whole number.

Two small balls, A and B, attract each other gravitationally with a force of magnitude f. If we now double both masses and the separation of the balls, what will now be the magnitude of the attractive force on each one?

F

Two small objects, with masses m and M, are originally a distance r apart, and the magnitude of the gravitational force on each one is F. The masses are changed to 2m and 2M, and the distance is changed to 4r. What is the magnitude of the new gravitational force?

F/4

Two children, Ahmed and Jacques, ride on a merry-go-round. Ahmed is at a greater distance from the axis of rotation than Jacques. What is true about their angular and tangential speed?

Jacques and Ahmed have the same angular speed but Ahmed has a greater tangential speed than Jacques.

Two simple pendulums, A and B, are each 3 m long, and the period of pendulum A is T. Pendulum A is twice as heavy as pendulum B. What is the period of pendulum B?

T

A simple pendulum has a period T on Earth. If it were used on Planet X, where the acceleration due to gravity is three times what it is on Earth, what would its period be?

T / root 3

A ball is attached to an ideal spring and oscillates with a period T. If the mass of the ball is doubled, what is the new period?

T root 2

If you stood on a planet having a mass four times that of Earth's mass, and a radius two times that of Earth's radius, what would you weigh?

The same as you do on Earth

A pipe of length L that is open at both ends is resonating at its fundamental frequency. What is true about the wavelength and where the displacement nodes/antinodes are?

The wavelength is 2L and there is a displacement node at the pipe's midpoint.

X and Y are two initially uncharged metal spheres on insulating stands, and they are in contact with each other. A positively charged rod R is brought close to X. Sphere Y is now moved away from X. What are the final charge states of X and Y?

X is negative and Y is positive

The figure shows scale drawings of four objects, each of the same mass and uniform thickness, with the mass distributed uniformly. Which one has the greatest moment of inertia when rotated about an axis perpendicular to the plane of the drawing at point P?

a wheel like figure