derive the expression for rotational kinetic energy..
Answers
i think it should also be in your text book
Consider of a body of mass m moving with velocity v the body stops after moving through some distance S due to some opposing force such as force of friction acting on it. The body posses kinetic energy and is capable to do work against opposing force F until all its kinetic energy is used up
Derivation:
K.E. of the body. = Work done by it due to motion
K.E.= FS
Vi = V
Vf = 0
As F = ma
∴ a = -F/m (retardation)
Since motion is opposed, hence, a is negative.
Using 3rd equation of motion:
2 a S = Vf² - Vi²
2 (-F/m) S= (0)² - (Vi)²
F S= 1/2 m v²
As K.E, is equal to FS we get
K.E.=1/2 m v²