A flywheel of mass 0.2 kg and radius 10 cm is rotating with `5/pi (rev)/s` about an axis perpendicular to its plane passing through its centre. Calculate angular momentum and kinetic energy of flywheel.

Explanation

Angular velocity, `omega=2pixx(5)/(pi)=10 "rad/s"`
and moment of inertia, `I=mr^(2)=(0.2)(0.1)^(2)=2xx10^(-3)"kg-m"^(2)`
Angular momentum `= I omega=2xx10^(-3)xx10=2xx10^(-2) "J-s"`
or `=2xx10^(-2) "kgm"^(2)s^(-1)`
Kinetic energy `= (1)/(2)I omega^(2)=(1)/(2)xx2xx10^(-3)xx(10)^(2)=0.1J`.