Circular Motion and Gravitation

Centripetal acceleration must involve a change in

• an object’s tangential speed.

• an object’s velocity.

• both an object’s speed and direction.

• the radius of an object’s circular motion.

What is the speed of an object in circular motion called?

• circular speed

• centripetal speed

• tangential speed

• inertial speed

Which of the following is the correct equation for centripetal acceleration?

• a_c = v_t² / r

• a_c = v_t / r

• a_c = mv_t² / r

• a_c = (v_tf G_ti )/ Δt

What is the centripetal acceleration of a skater moving with a tangential speed of 2.0 m/s in a circular path with radius 2.0 m?

• 1.0 m/s²

• 2.0 m/s²

• 4.0 m/s²

• 8.0 m/s²

What term describes a force that causes an object to move in a circular path?

• circular force

• centripetal acceleration

• centripetal force

• centrifugal force

A centripetal force acts

• in the same direction as tangential speed.

• in the direction opposite tangential speed.

• perpendicular to the plane of circular motion.

• perpendicular to tangential speed but in the same plane.

Centripetal force can be calculated from centripetal acceleration by

• dividing by the mass.

• multiplying by the mass.

• squaring the acceleration and dividing by the radius.

• squaring the acceleration, multiplying by the mass, and dividing by the radius.

Which of the following is due to inertia?

• A ball whirled in a circular motion stays in one plane.

• A ball whirled in a circular motion experiences centripetal acceleration directed toward the center of motion.

• A ball whirled in a circular motion experiences a centripetal force directed toward the center of motion.

• A ball whirled in a circular motion will move off in a straight line if the string breaks.

A 1.3 x 10³ kg car traveling with a speed of 2.5 m/s executes a turn with a 7.5 m radius of curvature. Calculate the centripetal acceleration of the car and the centripetal force acting on the car.

• 0.33 m2 /s, 0.429 N

• 0.33 m2 /s, 4.29 x 10² N

• 0.83 m2 /s, 1.08 x 10³ N

• 0.83 m2 /s, 4.29 x 10² N

________ between a race car’s tires and a circular track is a centripetal force that keeps the car in a circular path.

• Gravity

• Friction

• Inertia

• Velocity