Why use F=mv²/r instead of τ=Iα for circular motion

[tee yeh hun]

After understanding about torque,

I got one question about it.

Why we can't use it as τ =Iα istead of F=mv^2/r ?


since both are forces about circular motion

 

[Doc Al]

They describe different aspects of circular motion.

When do we use F=mv^2/r ?

This describes the centripetal (radial) force acting on an object that is moving in a circle at some speed.

Why we can't use it as τ =Iα

This describes the torque necessary to give some object (with rotational inertia I) an angular acceleration.

If something moves in a circle at constant speed, then the angular acceleration is zero--no torque is needed. But there will be a centripetal force on the object.

 

[tee yeh hun]

thx ...