physics help please!!!
posted by Anonymous .
What is the angular momentum of a 2.5 kg uniform cylindrical grinding wheel of radius 19 cm when rotating at 1200 rpm? And how much torque is required to stop it in 5.7 s? Need help with stepbystep explanation.

chose your moment of Inertia model. I think solid disk is a good model. I= 1/2 mr^2
angMomentum= I*angvelocity
where w (angular velocity)=2PI*1200/60 rad /seconds
Torque=momentinertia*angularacceleration
= 1/2 m r^2 * change in angvelocity/time
= 1/2 m r^2 * (wfwi)/5.7sec
wf=0 ; wi is 2PI*1200/60 rad/sec
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