Chap 8 Review

Chap 8 Review

Chap 8.1

• angular displacement x=rƟ

• angular velocity w=Δω/ΔΤ

• acceleration a=rα

• Angular acceleration α=Δω/ΔΤ

• Distance X=rΘ

• Velocity V=rω

Multiple Choice

If a truck has a linear acceleration of 1.85 m/s2 and the wheels have an angular acceleration of 5.23 rad/s2, what is the diameter of the truck’s wheels?

• 0.707

• 9.68

• 2.83

Multiple Choice

The outer edge of a truck tire that has a radius of 45 cm has a velocity of 23 m/s. What is the angular velocity of the tire in rad/s

• 0.51 rad.sec

• 51 rad/sec

• 1.96 rad/sec

Remember, to change rev/min

• multiply rev x 2 π

• then make sure to divide by correct time

Multiple Choice

In the spin cycle of a clothes washer, the drum turns at 635 rev/min. If the lid of the washer is opened, the motor is turned off. If the drum requires 8.0 s to slow to a stop, what is the angular acceleration of the drum?

• 79 rad/sec

• 498 rad/sec

• 8.3 rad/sec

Multiple Select

An airplance propeller slows from 475 rev/min to 187 rev/min in 4.00 s. What is its angular acceleration?

• 72 rad/s²

• 30 rad/s²

• 7.54 rad/s²

Multiple Choice

You are doing your laundry. When the washing machine goes into its spin cycle, the tub starts from an angular speed of 2.30 rad/s. It then speeds up smoothly for 8.00 s until it is turning at 5.00 rev/s. Calculate the angular acceleration of the tub during this time.

• 1.16 rad/s²

• 3.64 rad/s²

• 0.64 rad/s²

Force and Angular Velocity

• Recall, Τ=Frsinθ

• If min or max, then sin Θ= 90

Multiple Choice

A bolt is to be tightened with a torque of 8.0 N∙m. If you have a wrench that is 0.35 m long, what is the least amount of force you must exert?

• 0.23 N

• 23 N

• 4.4 N

Multiple Choice

What is the torque on a bolt produced by a 15-N force exerted perpendicular to a wrench that is 25 cm long, as shown

• 375

• 60

• 3.8

Balanced Forces Review

• Recall Τ=Frsinθ

• So, if balanced T₁=T₂

• or Fr₁=Fr₂

Multiple Choice

Chloe, whose mass is 56 kg, sits 1.2 m from the center of a seesaw. Josh, whose mass is 84 kg, wants to balance Chloe. Where on the seesaw should Josh sit?

• 0.8

• 1.8

• 0.65

Multiple Choice

Quanda has a mass of 50.0 kg and sits 2.25 m from the center of a seesaw. Jabari balances by sitting 3.55 m from Quanda. What is Jabari’s mass?

• 31

• 26.6

• 86.5

• 112.5