Question

A flywheel of mass 4 kg has radius of gyration 0.4 calculate the kinetic energy of rotation when it makes 5 r.p.s

Answer 1

Therefore the kinetic energy of rotation is 32π² Joule.

Given : A flywheel of mass 4 kg has radius of gyration 0.4.

To find : The kinetic energy of rotation when it makes 5 revolution per second.

solution : mass of flywheel , m = 4kg

radius of gyration, K = 0.4 m

so moment of inertia of flywheel, I = mK²

= 4kg × (0.4m)² = 0.64 kgm²

now kinetic energy of rotation, K.E = 1/2 Iω²

here angular velocity, ω = 5 revolution per second = 5 × 2π rad/s = 10π rad/s

K.E = 1/2 × 0.64 × (10π)²

= 0.32 × 100π²

= 32π² Joule

Therefore the kinetic energy of rotation is 32π² Joule.