Circular Motion

Circular Motion

Centripetal Acceleration

Centripetal acceleration points in the direction of the center of the circle. Even though the velocity of the circle motion remains constant, the object is accelerating because it is constantly changing direction.

The formula for Centripetal Acceleration is:

a_c = v²/r

Centripetal Force

Centripetal force is the force on an object that makes go in a circle. The force is always directed toward the center of the circle.

F=mv²/r

Multiple Choice

A 450 kg car travelling at 20 m/s goes around a curve with a radius of 15 m. Determine the centripetal acceleration of the car?

• 600 m/s/s

• 26.7 m/s/s

• 1.3 m/s/s

• 0.67 m/s/s

Multiple Choice

A .4 kg stone is attached to a rope. If you swing the stone in a circle over your head at a constant speed of 4 m/s, and the length of the rope is .8 m, what is the centripetal acceleration of the stone, and how much force do you have to apply to keep it spinning?

• a=20 m/s/s

  F=8 N

• a=20 m/s/s

  F=5.12 N

• a=5 m/s/s

  F=0.004 N

• a=5m/s/s

  F=3.2 N