Unit 7 Review

A solid cylinder with a radius of 0.60 m rolls, without slipping, down a hill. What is the height of the hill if the final velocity of the block is 11.0 m/s? Use g = 10 m/s².

I = ½ MR²

• 3 m

• 6 m

• 9 m

• 12 m

Giancoli p. 220, #25

• zero

See conceptual example 8-14 on p. 212. Who wins the race to the bottom? Why?

• Sphere, lowest I value

• Hoop, highest I value

• Solid cylinder, rolls with lowest friction

• Empty Can, smallest mass

Four children climb on a carousel that is initially at rest. If the carousel accelerates to 0.4 rad/s in 10 s, what is the angular acceleration?

• cannot answer without knowing the radius

An aluminum pie plate of radius 0.12 m is spins and accelerates at a constant rate from 13 rad/s to 29 rad/s in 5.4 s.  What was its angular displacement during that time?

• 113 radians

• 13.6 m

• 57 radians

• 229 radians

What torque needs to be applied to an antique sewing machine spinning wheel of radius 0.28 m and mass 3.1 kg (model it as a hoop, with I = MR²) to give it an angular acceleration of 4.8 rad/s²?

• 0.59 N*m

• 4.2 N*m

• 1.17 N*m

• 0.05 N*m

You spin a ball of mass 0.18 kg that is attached to a string of length 0.98 m at ω = 5.2 rad/s in a circle.  What is the ball’s angular momentum?

• Cannot answer without an I value

• -3.45