Circular Motion

What is the period of motion of the boy in the figure?

• 0.50 s

• 2.00 s

• 5.00 s

• 10.0 s

The figure shows a ball travelling in a circle. Which vector represents the tangential velocity?

• Vector A

• Vector B

• Vector C

• Vector D

For a particular circular motion situation, the velocity is doubled, and the period is tripled. All other variables remain the same. What factor does the centripetal acceleration change by?

• $a_{new}\ =\left(\frac{2}{3}\right)a_{old}$

• $a_{new}\ =\left(\frac{4}{3}\right)a_{old}$

• $a_{new}\ =\left(\frac{4\pi}{3}\right)a_{old}$

• $a_{new}\ =\left(\frac{3}{2}\right)a_{old}$

When a car goes around a circular curve on a level road, ...

• no frictional force is needed because the car simply follows the road.

• the frictional force of the road on the car increases when the car's speed decreases.

• the frictional force of the road on the car increases when the car's speed increases.

• the frictional force of the road on the car increases when the car moves to the outside of the curve.

A rock attached to a string swings in vertical circle. Which free body diagram could correctly describe the force(s) on the rock when the string is in one possible horizontal position?

• A

• B

• C

• D

Calculate the velocity of an object moved around a circle with a radius of 1.65 m and an acceleration of $3.5m/s^2$ .

•  $2.4\ m/s\$  

•  $3.6\ m/s$  

•  $3.9\ m/s$  

•  $4.2\ m/s$  

Calculate the mass of an object if it took 20 N to rotate it in a circle with a radius of 2 meters with a velocity of 4 m/s.

• 4.1 kg

• 3.6 kg

• 2.5 kg

• 1.8 kg

Calculate the centripetal force required to make a 5 kg ball move 4 m/s in a circle with a radius of 2 m.

• 10 N

• 20 N

• 30 N

• 40 N

A small sphere is swung in a vertical circle. Which of the following combinations represents the direction of the velocity and acceleration at the bottom of the circle?

• A

• B

• C

• D

A small sphere is swung in a vertical circle. Which of the following combinations represents the direction of the velocity and acceleration at the right-most point of the circle?

• A

• B

• C

• D