# Acceleration problem

1. Apr 8, 2009

### tnutty

1. The problem statement, all variables and given/known data

A wheel is spinning at 43rpm with its spin axis vertical. After 15s , it's spinning at 62rpm with its axis horizontal. Find (a) the magnitude of its average angular acceleration.

2. Relevant equations

$$\alpha$$ = $$\varpi$$ /t

attempt :

change in omega is 2pi/60 (62-43)
t = 15
so divide them to get rad/s/s
=
1.3 * 10^-1

2. Apr 8, 2009

### rl.bhat

First of all find the angular momentum L.
Then find the rate of change of angular momentum.
Note that L is a vector.So when you find change in L, you have to use vector subtraction. Finally equate it to I*alpha.