A mass of `5kg` is moving along a circular path or radius `1m`. If the mass moves with 300 revolutions per minute, its kinetic energy would be

Options

A. `250pi^2 J`
B. `100 pi^2 J`
C. `5pi^2 J`
D. 0 J

Answer

A

Explanation

Here,
Mass, m=5 kg, Radius ,R=1 m
`upsilon`=300 rpm =`300/60` rps = 5 rps
The angular speed is given by
`omega=2piupsilon =2pixx5=10 pi "rad" s^(-1)`
The linear speed is
`v=omegaR=(10pi s^(-1)) (1 m) = 10 pi m s^(-1)`
Kinetic energy, `K=1/2mv^2`
`K=1/2xx(5 kg) (10 pi m s^(-1))^2 =250pi^2 J`