Determine the kinetic energy of a circular disc rotating with a speed of 60 rpm about an axis passing through a point on its circumference and perpendicular to its plane. The circular disc has a mass of 5 kg and radius 1 m.

Options

A. 170 J
B. 160 J
C. 150 J
D. 140 J

Answer

C

Explanation

The rotational kinetic energy is given by `KE=(1)/(2)Iomega^(2)=(1)/(2)xx(3)/(2)mr^(2)4pi^(2)f^(2)`
where, m=mass, r=radius and f=frequency
`Rightarrow KE=3mr^(2)xxpi^(2)f^(2)=3xx5xx1xx10xx1`
`Rightarrow KE=150J`