Question

If a disk is rotating from rest with an angular acceleration of 1.72 rad/s^2 for 5.67 seconds, what is its final rotational kinetic energy? Take the moment of inertia of the disk to be 0.692 kg*m^2.

Answer 1

Moment of inertia of the disk = I = 0.692 kg.m²

Initial angular speed of the disk = ₁ = 0 rad/s (At rest)

Final angular speed of the disk = ₂

Angular acceleration of the disk = = 1.72 rad/s²

Time period = T = 5.67 sec

₂ = ₁ + T

₂ = 0 + (1.72)(5.67)

₂ = 9.75 rad/s

Final rotational kinetic energy of the disk = E

E = 32.9 J

Final rotational kinetic energy of the disk = 32.9 J