Question

A body of mass 1 kg starts moving from rest at t = 0, in a circular path of radius 8 m. Its kinetic energy varies as a function of time as KE = 2t² J, where t is in seconds. Then –

• A. Tangential acceleration = 4 m/s²
• B. Power of all forces at t = 2 s is 8 W
• C. First round is completed in 2 s
• D. Tangential force at t = 2 s is 4 N

Answer 1

Answer: (B)

Power of all forces at t = 2 s is 8 W

Answer 2

$\frac{1}{2}$mv­² = 2t² ̃ mv² = 4t²

̃ v = 2t [m = 1kg]

So power can be calculate.