UCM and Gravitation

A boy and a girl are riding a merry-go-round which is turning at a constant rate. The boy is near the outer edge, while the girl is closer to the center. Who has the greater tangential acceleration? Select one: a. the girl b. There is not enough information given to answer the question. c. Both have zero tangential acceleration. d. the boy e. Both have the same non-zero tangential acceleration.

both have zero tangential acceleration

If the sun were twice as massive Select one: a. the pull of the Earth on the sun would double. b. neither of these c. both of these d. its pull on the Earth would double.

both of these

A supplier wants to make a profit by buying metal by weight at one altitude and selling it at the same price per pound at another altitude. The supplier should Select one: a. buy at a high altitude and sell at a low altitude. b. buy at a low altitude and sell at a high altitude. c. disregard altitude because it makes no difference. d. buy at night and sell during the day

buy at a high altitude and sell at a low altitude

What type of acceleration does an object moving with constant speed in a circular path experience? Select one: a. constant acceleration b. linear acceleration c. free fall d. centripetal acceleration

centripetal acceleration

What force is needed to make an object move in a circle? Select one: a. kinetic friction b. static friction c. centripetal force d. weight

centripetal force

What is the term for the net force directed toward the center of an object's circular path? Select one: a. centrifugal force b. centripetal force c. circular force d. orbital force

centripetal force

The movement of an object or a point mass at a constant speed around a circle that has a fixed radius is called uniform: Select one: a. circular motion b. rotational motion c. parabolic motion d. elliptical motion

circular motion

If a turntable's rotational speed is doubled, then the linear speed of a pet hamster sitting on the edge of the record will Select one: a. halve. b. quadruple c. remain the same. d. double.

double

Two objects move toward each other because of gravity. As the objects get closer and closer, the force between them Select one: a. remains constant. b. decreases, then increases. c. increases, then decreases. d. decreases. e. increases.

increases

A ball is whirled on a string, then the string breaks. What causes the ball to move off in a straight line? Select one: a. centripetal acceleration b. centripetal force c. inertia d. centrifugal force

inertia

When a car makes a sharp left turn, what causes the passengers to move toward the right side of the car? Select one: a. centripetal acceleration b. inertia c. centripetal force d. centrifugal force

inertia

When an object is moving with uniform circular motion, the object's tangential speed Select one: a. is directed toward the center of motion. b. is circular. c. is perpendicular to the plane of motion. d. is constant.

is constant

When an object is moving with uniform circular motion, the centripetal acceleration of the object Select one: a. is perpendicular to the plane of motion. b. is zero. c. is circular. d. is directed toward the center of motion.

is directed toward the center of motion

When an object experiences uniform circular motion, the direction of the acceleration is Select one: a. in the same direction as the velocity vector. b. in the opposite direction of the velocity vector. c. is directed toward the center of the circular path. d. is directed away from the center of the circular path.

is directed toward the center of the circular path

A "weightless" astronaut in an orbiting shuttle is Select one: a. like the shuttle, pulled by Earth's gravitation. b. beyond the pull of gravity. c. none of these d. shielded from the Earth's gravitational field. e. pulled only by gravitation to the shuttle which cancels the Earth's gravitational pull.

like the shuttle, pulled by Earth's gravitation

A weight watcher who normally weighs 400 N stands on top of a very tall ladder so she is one Earth radius above the Earth's surface. How much would she weigh there? Select one: a. none of these b. 100 N c. 0 d. 400 N e. 200 N

100 N

An asteroid exerts a 360-N gravitational force on a nearby spacecraft. If the spacecraft moves to a position three times as far from the center of the asteroid, the force will be Select one: a. 120 N. b. 360 N. c. zero. d. 40 N. e. 1080 N.

40 N

According to Newton, doubling the distance between two interacting objects Select one: a. divides by 2 the gravitational force between them. b. divides by 4 the gravitational force between them. c. multiplies by 2 the gravitational force between them. d. multiplies by 4 the gravitational force between them.

divides by 4 the gravitational force between them

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 Select one: a. doubles. b. halves. c. remains the same.

doubles

A circular racetrack has a circumference of 6.5km. What angular speed, in radians per second, does a racecar have if it has a linear speed of 243km/hr? Select one: a. 0.235 rad/sec b. 0.000065 rad/sec c. 0.85 rad/sec d. 0.065 rad/sec

0.065 rad/sec

Two children are riding on a merry-go-round. Child A is at a greater distance from the axis of rotation than child B. Which child has the larger centripetal acceleration? Select one: a. They have the same non-zero centripetal acceleration. b. They have the same zero centripetal acceleration. c. There is not enough information given to answer the question. d. Child B e. Child A

Child A

Two children are riding on a merry-go-round. Child A is at a greater distance from the axis of rotation than child B. Which child has the larger linear displacement? Select one: a. Child B b. They have the same non-zero linear displacement. c. There is not enough information given to answer the question. d. They have the same zero linear displacement. e. Child A

Child A

An object is placed exactly halfway between the Earth and moon. The object will fall toward the Select one: a. none of these b. Sun c. moon. d. Earth.

Earth

Consider a particle moving with constant speed such that its acceleration of constant magnitude is always perpendicular to its velocity. Select one: a. It is moving in a straight line. b. None of the above is definitely true all of the time. c. It is moving in a parabola. d. It is moving in a circle.

It is moving in a circle

Two children ride on a merry-go-round, George is at a greater distance from the axis of rotation than Jacques. It is a true statement that Select one: a. Cannot tell which one has the greater angular velocity without knowing their masses. b. both have zero angular velocities. c. Jacques has a greater angular velocity than George. d. Jacques has a smaller angular velocity than George. e. Jacques and George have the same angular velocity.

Jacques and George have the same angular velocity

Two children ride on a merry-go-round, George is at a greater distance from the axis of rotation than Jacques. It is a true statement that Select one: a. Jacques and George have the same tangential speed. b. Jacques has a smaller tangential speed than George. c. both have zero tangential speeds. d. Cannot tell which one has the greater speed without knowing their masses. e. Jacques has a greater tangential speed than George.

Jacques has a smaller tangential speed than George

The planet Jupiter is about 300 times as massive as Earth, yet on its surface you would weigh only about 3 times as much. This is because Select one: a. none of these b. Jupiter's radius is 10 times the Earth's radius. c. your mass is 100 times less on Jupiter. d. Jupiter is significantly farther from the sun. e. you are 100 times more weightless there.

Jupiter's radius is 10 times the Earth's surface

A space probe is directly between two moons of a planet. If it is twice as far from moon A as it is from moon B, but the net force on the probe is zero, what can be said about the relative masses of the moons? Select one: a. Moon A is twice as massive as moon B. b. Moon A is half as massive as moon B. c. Moon A has the same mass as moon B. d. Moon A is four times as massive as moon B.

Moon A is four times as massive as moon B

What prevents satellites such as the space shuttle from falling? Select one: a. the absence of air drag b. gravity c. Nothing; they are continually falling as they orbit the Earth. d. centripetal force e. centrifugal force

Nothing; they are continually falling as they orbit the Earth

Two children are on a merry-go-round. Which child has the faster linear speed? Select one: a. The child near the center. b. Impossible to say without knowing the angular speed. c. The child near the edge. d. They both have the same speed.

The child near the edge

Two children of equal mass are on a merry-go-round. Which child experiences the greater centripetal force? Select one: a. The child near the edge. b. They both have the same centripetal force. c. Impossible to say without knowing the linear speed. d. The child near the center.

The child near the edge

Why does an astronaut weigh less on the moon than on Earth? Select one: a. The astronaut has less mass on the moon. b. The gravitational field strength is less on the moon's surface than on Earth's surface. c. The astronaut is continually in free fall because the moon orbits Earth. d. The astronaut is farther from Earth's center when he or she is on the moon.

The gravitational field strength is less on the moon's surface than on the Earth's surface

A machine part is measured to have an angular speed of 67rad/sec. What is the time period for one revolution? Select one: a. 0.094 s b. 10.7 s c. 0.047 s d. 34 s

0.094 s

A circular racetrack has a circumference of 6.3km. What angular speed, in revolutions per minute, does a racecar have if it has a linear speed of 199km/hr? Select one: a. 1.895 rpm b. 0.526 rpm c. 6.82 rpm d. 0.000526 rpm

0.526 rpm

Two children are on a merry-go-round. Billy is a distance r from the center and Willy is a distance 3r from the center. What is the ratio of Willy's period of revolution to Billy's period of revolution? Select one: a. 3 b. 1/3 c. 1 d. 9

1

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 Select one: a. 2 m/s. b. 1 m/s. c. 3 m/s. d. 3.14 m/s. e. 6.28 m/s.

2 m/s

What is the approximate angular speed of the earth as it orbits the sun in radians per second? Select one: a. 2´10-5 radians/second b. 2´10-7 radians/second c. 5´10-6 radians/second d. 2´108 radians/second

2´10-7 radians/second

Two children are on a merry-go-round. Billy is a distance r from the center and Willy is a distance 3r from the center. What is the ratio of Willy's centripetal acceleration to Billy's centripetal acceleration? Select one: a. 3 b. 1 c. 1/3 d. 9

3

Two children are on a merry-go-round. Billy is a distance r from the center and Willy is a distance 3r from the center. What is the ratio of Willy's linear speed to Billy's linear speed? Select one: a. 3 b. 1 c. 1/3 d. 9

3

A disk spins at a rate of 49.09 revolutions per second. Calculate the angular speed in radians per second. Select one: a. 308.4 radians/second b. 0.8568 radians/second c. 154.2 radians/second d. 7.813 radians/second

308.4 radians/second

A disk spins and makes 52.09 revolutions. Through how many radians did the disk spin? Select one: a. 0.9091 radians b. 8.290 radians c. 327.3 radians d. 163.6 radians

327.3 radians

A disk with a diameter of 20cm spins at a rate of 32.44 revolutions per minute. Calculate the linear speed of the edge of the disk in cm/s.. Select one: a. 34 cm/s b. 2038 cm/s c. 52 cm/s d. 1019 cm/s

34 cm/s

A disk spins at a rate of 55.78 revolutions per minute. Calculate the angular speed in radians per second. Select one: a. 8.878 radians/second b. 350.5 radians/second c. 5.841 radians/second d. 175.2 radians/second

5.841 radians/second

What is the force of gravity on a 500-newton woman standing on the Earth's surface? Select one: a. 500 N b. none of these c. 5000 N d. 250 N e. 50 N

500 N

Two children are riding on a merry-go-round. Child A is at a greater distance from the axis of rotation than child B. Which child has the larger tangential acceleration? Select one: a. There is not enough information given to answer the question. b. Child B c. They have the same non-zero centripetal acceleration. d. They have the same zero centripetal acceleration. e. Child A

Child A

Two children are riding on a merry-go-round. Child A is at a greater distance from the axis of rotation than child B. Which child has the larger tangential speed? Select one: a. They have the same zero tangential speed. b. They have the same non-zero tangential speed. c. Child B d. Child A e. There is not enough information given to answer the question.

Child A

An object moves in a circular path at a constant speed. Compare the direction of the object's velocity and acceleration vectors. Select one: a. The vectors point in opposite directions. b. Both vectors point in the same direction. c. The question is meaningless, since the acceleration is zero. d. The vectors are perpendicular.

The vectors are perpendicular

Two children are on a merry-go-round. Which child has the faster angular speed? Select one: a. They both have the same speed. b. Impossible to say without knowing the linear speed. c. The child near the center. d. The child near the edge.

They both have the same speed

Two children are riding on a merry-go-round. Child A is at a greater distance from the axis of rotation than child B. Which child has the larger angular displacement? Select one: a. They have the same zero angular displacement. b. There is not enough information given to answer the question. c. They have the same non-zero angular displacement. d. Child B e. Child A

They have the same non-zero angular displacement

Two children are riding on a merry-go-round. Child A is at a greater distance from the axis of rotation than child B. Which child has the larger angular speed? Select one: a. There is not enough information given to answer the question. b. Child A c. Child B d. They have the same non-zero angular speed. e. They have the same zero angular speed.

They have the same non-zero angular speed

Is it possible for an object moving with a constant speed to accelerate? Explain. Select one: a. No, an object can accelerate only if there is a net force acting on it. b. No, if the speed is constant then the acceleration is equal to zero. c. Yes, if an object is moving it can experience acceleration d. Yes, although the speed is constant, the direction of the velocity can be changing.

Yes, although the speed is constant, the direction of the velocity can be changing

Which of the following can be a centripetal force? Select one: a. tension b. friction c. gravity d. all of the above

all of the above

The circular path of a satellite orbiting the Earth is characterized by a constant Select one: a. none of these b. speed. c. acceleration. d. all of these e. radial distance.

all of these

The amount of gravitational force that acts on the space shuttle while in orbit is Select one: a. nearly zero. b. the same as the shuttle's weight on the Earth's surface. c. almost as much as the shuttle's weight on the Earth's surface. d. more than the shuttle's weight on the Earth's surface.

almost as much as the shuttle's weight on the Earth's surface

When calculating the gravitational force between two extended bodies, you should measure the distance Select one: a. from the closest points on each body. b. from the most distant points on each body. c. from the center of one body to the closest point on the other body. d. from the center of each body.

from the center of each body

According to Newton, the greater the masses of interacting objects, the Select one: a. greater the gravitational force between them. b. greater the force between them by the square of the masses. c. gravitational force between them is constant d. less the gravitational force between them.

greater the gravitational force between them

When an object experiences uniform circular motion, the direction of the net force is Select one: a. in the opposite direction of the motion of the object. b. in the same direction as the motion of the object. c. is directed toward the center of the circular path. d. is directed away from the center of the circular path.

is directed toward the center of the circular path

A woman on the surface of the Earth has a mass of 50 kilograms and a weight of 490 newtons. If the woman were floating freely inside a space habitat far away from Earth, she would have Select one: a. none of these b. less weight and less mass. c. less weight and more mass. d. more weight and less mass. e. less weight and the same mass.

less weight and the same mass

The reason the moon does not crash into the Earth is that the Select one: a. moon has a sufficient tangential speed. b. Earth's gravitational field is weak at the moon. c. moon has less mass than the Earth. d. none of these e. gravitational pull of other planets keeps the moon up.

moon has a sufficient tangential speed

Horses that move with the fastest linear speed on a merry-go-round are located Select one: a. anywhere, because they all move at the same speed. b. near the center. c. higher above the ground d. near the outside.

near the outside

Consider two planets in space that gravitationally attract each other. If the masses of both planets are doubled, and the distance between them is also doubled, then the force between them is Select one: a. none of these b. one quarter. c. twice as much. d. four times as much. e. half as much.

none of these

A car goes around a curve of radius r at a constant speed v. Then it goes around the same curve at half of the original speed. What is the centripetal force on the car as it goes around the curve for the second time, compared to the first time? Select one: a. four times as big b. one-fourth as big c. half as big d. twice as big

one-fourth as big

The period of a satellite, the time it takes for a complete revolution, depends on the satellite's Select one: a. mass. b. none of these c. radial distance. d. all of these e. weight.

radial distance

Angular velocity is expressed in units of Select one: a. radians per second. b. arcs per second. c. meters per second. d. omegas per second.

radians per second

Angular acceleration is expressed in units of Select one: a. alphas per second squared. b. meters per second squared. c. arcs per second squared. d. radians per second squared.

radians per second squared

If you drop a stone into a hole drilled all the way to the other side of the Earth (neglect the molten core), the stone will Select one: a. speed up until it reaches the other side of the Earth. b. slow down until it reaches the center. c. come to an abrupt stop at the center of the Earth. d. speed up until it gets to the center of the Earth.

speed up until it gets to the center of the Earth

A car goes around a curve of radius r at a constant speed v. Then it goes around a curve of radius 2r at speed 2v. What is the centripetal force on the car as it goes around the second curve, compared to the first? Select one: a. twice as big b. one-fourth as big c. one-half as big d. four times as big

twice as big

The fastest moving planet in a solar system is Select one: a. the planet farthest from the sun. b. the planet nearest the sun. c. the smallest planet. d. any planet, for they all move at the same speed. e. the most massive planet.

the planet nearest the sun

The speeds of the planets about the sun depend on Select one: a. their periods of rotation. b. the masses of the planets. c. their distances from the sun. d. None of the above are correct.

their distances from the sun

Planets would crash into the sun if it weren't for Select one: a. the fact that they are beyond the main gravitation of the sun. b. the inverse-square law. c. their tangential velocities. d. their relatively small masses. e. their vast distances from the sun.

their tangential velocties

A car goes around a curve of radius r at a constant speed v. What is the direction of the net force on the car? Select one: a. away from the curve's center b. toward the back of the car c. toward the curve's center d. toward the front of the car

toward the curve's center