Calculus-Based Physics by Jeffrey W. Schnick - HTML preview

Chapter 5 Conservation of Angular Momentum

Example 5-1

A skater is spinning at 32.0 rad/s with her arms and legs extended outward. In this

position her moment of inertia with respect to the vertical axis about which she is

spinning is

2

45 6

. kg ⋅ m . She pulls her arms and legs in close to her body changing

her moment of inertia to

2

17.5 kg ⋅ m . What is her new angular velocity?

BEFORE

AFTER

rad

w = 32.0

w ′ = ?

s

I

= 45.6 kg⋅m2

I′ = 17.5 kg⋅m2

L

= L′

Iw = ′

Iw′

I

w′ =

w

′

I

45 6

. kg ⋅ m2

w′ =

32.0 rad / s

17 5

. kg ⋅ m2

rad

w′ = 83.4 s

28