Question

hey anyone knowhow to calculate newtons laws on angular motion ?
Q, what torque is reqiired to produce an angular acceleration of 40 rads/s sq in a wheel that has a moment of inertia of 400gk-m sq ?

Answer 1

You have:
\[\alpha=30\frac{1}{s^2}\quad I=400\ kg\cdot m^2\]
For angular acceleration alpha, torque T and moment of inertia I we have:
\[
T=I\cdot \alpha
\]
and the answer to your question is:
\[
T=400kg\cdot m^2\cdot 30\frac{1}{s^2}=12000\ Nm.
\]
To study more, see:
http://en.wikipedia.org/wiki/Uniform_circular_motion
http://en.wikipedia.org/wiki/Moment_of_inertia

Answer 2

a is actually 40, which makes the answer 16000. The rest is right :D