Circular Motion Test Review

A motorcycle travels around a flat circular track. If the speed of the motorcycle is increases, the force required to keep it on the track________________

increases

When an object experiences uniform circular motion, the direction of the object's acceleration is

is directed toward the center of the circular path

For uniform circular motion, if the radius is cut in half, the centripetal acceleration?

it is twice its original value

Issac Newton called acceleration toward the center, _______________acceleration.

Centripetal Force

A motorcycle has a mass of 250 kg. It goes around a 13.7 m radius turn at 26.8 m/s. What is the centripetal force on the motorcycle?

1.31x10^4 N

Which planets have a period of rotation around the Sun greater than 1 Earth year? 1. Those farther from the sun 2. Those closer to the sun 3. It depends on the planet's mass. 4. Additional information is needed.

1.Those father from the sun

The speed of an object moving in uniform circular motion can be found by

2(pi)r/T

How does the force of gravity between two bodies change when the distance between them doubles? 1. Unable to determine; the mass is needed. 2. drops to one quarter of its original value 3. quadruples 4. doubles 5. halves 6. remains the same

2. drops to one quarter of its original value

A ball is being swung in a horizontal circle at the end of a string at constant speed. Which statement is wrong? 1. The magnitude of ⃗a depends on the ball's speed and the radius of the circle. 2. While the acceleration ⃗a of the ball is not constant, its magnitude a is constant. 3. The acceleration vector ⃗a always points directly away from the center of the circle. 4. The vectors ⃗a and ⃗v are always precisely perpendicular to one another. 5. While the velocity ⃗v of the ball is not constant, its magnitude v is constant.

3. The acceleration vector ⃗a always points directly away from the center of the circle.

Two identical objects go around circles of identical diameter, but one object goes around the circle twice as fast as the other. The centripetal force required to keep the faster object on the circular path is 1. the same force required to keep the slower object on the path. 2. twice as much force as required to keep the slower object on the path. 3. one fourth as much force as required to keep the slower object on the path. 4. four times as much force as required to keep the slower object on the path.

4. four times as much force as required to keep the slower object on the path.

An object moves with constant speed of 30 m/s on a circular track of radius 150 m. What is the acceleration of the object?

6.0 m/s^2

In uniform circular motion, what is the angle between the radius and the velocity?

90 degrees

An object of mass m is moving with constant speed v in a circle of radius r. The net force acting on the object must INCREASE if 1. m increases. 2. v increases. 3. r decreases.

ALL 3

Which condition represents uniform circular motion?

An athlete running at constant speed on a circular track.

A body's velocity can change when its speed stays constant, if its changes.

Direction

An eraser is tied to the end of string. It is then whirled in a horizontal circle. A "God's eye" view of the eraser and its path is shown below. If the string snaps and the indicated position, which diagram illustrates the path of the eraser.

E, one with straight line off circle

In uniform circular motion, the velocity changes in both magnitude and direction.

FALSE

What is the unit for frequency?

Hz

An object moves with constant speed in a circular path. Which of the following statements is/are true? 1. The velocity is constant 2. The acceleration is constant. 3. The net force on the object is zero, since the speed is constant.

No statement is true

When you are in the front passenger seat of a car turning to the left, you may find yourself pressed against the right-side door. What concept(s) explain(s) why you press against the door and why the door presses on you?

Newton's First and Third Laws

Centrifugal force is not an actual force and merely a feeling due to one's inertia.

TRUE

A planet is an elliptical orbit about a star. What is also true?

The star is at a focus of the ellipse.The planet moves faster near the star than way from the star. The period does not depend on the mass of the planet

A car rounds a curve while maintaining a constant speed. Is there a net force on the car as it rounds the curve?

YES

Is it possible for an object moving with a constant speed to accelerate?

Yes, although the speed is constant, the direction of the velocity can be changing. (correct answer, your response)

What force is needed to make an object move in a circle?

centripetal force

An object traveling with uniform circular motion has centripetal acceleration due to the change in

direction

For uniform circular motion, what is the direction of the velocity?

tangent to the path

A car makes a left turn. The front-passenger claims that she feels a sensation of being pushed outward toward her side of the car. This is best explained by the fact that

the passenger has a natural tendency to move tangent to the path of the car

For uniform circular motion, what is the direction of the centripetal acceleration?

toward the center of the circle

For uniform circular motion, what is the direction of the centripetal force?

toward the center of the circle

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?

toward the center of the curve

To find centripetal force, multiply mass times _____.

v^2/r

What is the equation for centripetal acceleration?

v^2/r