Angular Momentum of a Tire (Help)

1. Mar 12, 2009

agentx

Problem:
A boy rolls a tire along a straight level street. The tire has mass 8.0 kg, radius 0.34 m and moment of inertia about its central axis of symmetry of 0.83 kg·m2. The boy pushes the tire forward away from him at a speed of 2.1 m/s and sees that the tire leans 10° to the right

Compare the change in angular momentum caused by this torque in 0.20 s to the original magnitude of angular momentum.
(change in momentum / original magnitude of angular momentum)

Relevant formulas:
L = Iw
v = Rw
L = rpsin(theta)

Attempted Solution:
w = 2.1m/s / .34 m = 6.176
L = Iw = (.83)(6.176) = 5.126

r = .2*2.1 = .42m
p = (8kg)(2.1)= 16.8
.42*16.8*sin(10) = 1.225

1.225/5.126 = .239

I was wondering if you could tell me what I'm doing wrong and walk me through the right process.

Thanks

2. Mar 12, 2009

Staff: Mentor

Moved to Homework Help forums.

Woof. Not a simple problem. But this makes it overly hard/obscure:

"Compare the change in angular momentum caused by this torque in 0.20 s to the original magnitude of angular momentum."

The units of torque are not seconds...

Last edited: Mar 12, 2009
3. Mar 12, 2009

Staff: Mentor

Welcome to the PF, BTW!