The angular momentum of a body changes by 80kg m^(2)s^(-1) when its angular velocity changes from 20 rad s^(-1) to 40 rad s^(-1). Find the change in its kinetic energy of rotation.

The angular momentum of a body changes by 80kg m^(2)s^(-1) when its an

1.	The angular momentum of a body changes by 80kg m^(2)s^(-1) when its angular velocity changes from 20 rad s^(-1) to 40 rad s^(-1). Find the change in its kinetic energy of rotation.
Answer» Solution :Change in angular momentum of the body `L_(2)-L_(1)=I(omega_(2)-omega_(1))` Change in KINETIC energy `=(1)/(2)L(omega_(2)^(2)-omega_(1)^(2))` `("change in K.E")/("change in angular momentum")=(omega_(2)+omega_(1))/(2)` `:.` change in K.E. `=80((20+40)/(2))=2400J`