unit 7 concept review

A proper conversion factor for degrees to radians would be

3pi=540

Marilyn (M) and her sister Sheila (S) are riding on a merry-go-round, as shown in Figure 7-1 (bird's-eye view).

They have different speeds, but the same angular velocity.

In uniform circular motion, there is a

constant angular velocity

The frequency unit of hertz is equivalent to

inverse seconds

When a rigid body rotates about a fixed axis all the points in the body have the same centripetal acceleration.

False

When a rigid body rotates about a fixed axis all the points in the body have the same linear displacement.

False

When a rigid body rotates about a fixed axis all the points in the body have the same tangential acceleration.

False

When a rigid body rotates about a fixed axis all the points in the body have the same tangential speed.

False

When a rigid body rotates about a fixed axis all the points in the body have the same angular acceleration.

True

When a rigid body rotates about a fixed axis all the points in the body have the same angular displacement.

True

When a rigid body rotates about a fixed axis all the points in the body have the same angular speed.

True

A car, driven around a circle with constant speed, must have

a centripetal acceleration.

The angular acceleration in circular motion

all the answers

James is twirling a rock around a horizontal circle on the end of a string. Figure 7-2 is a top view (motion is counterclockwise).

centripetal

If you whirl a tin can on the end of a string and the string suddenly breaks, the can will

fly off, tangent to its circular path

What is the direction of the force that acts on clothes in the spin cycle of a washing machine?

inward

A car travels in a circle with constant speed. The net force on the car

is directed toward the center of the curve

The radian unit is equivalent to a ratio of

length/length

Which of the following is NOT a unit of rotational speed?

meters per second

Does the centripetal force acting on an object do work on the object?

no, because the force and the displacement of the object are perpendicular

If the centripetal force on a particle in uniform circular motion is increased

the tangential speed will increase and/or the radius will decrease