Physics : Circular Acceleration

An automobile moves at a constant speed down one hill and up another hill along the smoothly curved surface shown below. 

Which of the following diagrams best represents the directions of the velocity and the acceleration of the automobile at the instant that it is at the lowest position, as shown?

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

• kinetic friction

• static friction

• weight

• centripetal force

Two children are on a merry-go-round.  Which child has the faster angular speed?

• Impossible to say without knowing LINEAR speed

• Trick question; they both have the SAME angular speed

• The kid that's near the center

• The kid that's closer to the edge

Two children are on a merry-go-round.  Which child has the faster linear speed?

• Impossible to say without knowing the angular speed.

• The child near the edge.

• They both have the same speed.

• The child near the center.

Two children are on a merry-go-round.  Which child has the faster centripetal acceleration?

• Impossible to say without knowing both Linear and Angular speed

• Trick question; they both have THE SAME centripetal acceleration

• The kid that's near the center

• The kid near the edge

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?

• 3

• 9

• 1/3

• 1

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?

• 3

• 9

• 1/3

• 1

Answer explanation

Linear Velocity = (Angular Velocity) x (Radius)

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?

• 3

• 9

• 1/3

• 1

Answer explanation

Linear Velocity = (Angular Velocity) x (Radius)

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

• remains the same

• halves

• doubles

• increases by 2–√

Answer explanation

What type of acceleration does an object moving with constant speed in a circular path experience?

• centripetal acceleration

• linear acceleration

• constant acceleration

• free fall