Rotation of Rigid Bodies

Question 1

Idealized model of a body that has an unchanging shape and size; it is void of deformations

Answer 1

Rigid body

has a definite shape and size

e.g. CD, ferris wheel, gears, ceiling fan, rotor blades of a helicopter

Question 2

where does the axis of rotation pass through

Answer 2

axis of rotation passes through origin and points out of page

angle θ from the +x-axis specificies a rigid body’s rotational position

Question 3

most natural way to measure angle θ in describing rotational motion

Answer 3

radians

Question 4

arc length formula

Answer 4

s = rθ

Question 5

conversion factors for radians

Answer 5

• 1 rad = 360° / 2π = 57.3°
• 1 rev/s = 2π rad/s
• 1 rev/min = 1 rpm = 2π / 60 rad/s