With part b. i need to find the speed.

Need in all of themmm only answer if you know plsssss

What is friction? how does it affect the motion of an object?

Asmall grinding wheel has a moment of inertia of 4.0×10−5 kg⋅m2 . what net torque must be applied to the wheel for its angular acceleration to be 150 rad/s2 ?