A horizontal 800 N merry go round is a solid disk of radius 1.50 m, started from rest by a constant horizontal force of 50.0 N applied tangentially to the edge of the disk. Find the kinetic energy of the disk after 3.00 s.

275.6 J

Explanation:

Weight, mg = 800 N

m = 800 / 9.8 = 81.63 kg

R = 1.5 m

F = 50 N

torque = I x α = F x R

where, I be the moment of inertia

α = F x R / I

now, ω = ωo + α t

ω = 0 + F x R x t / I

Kinetic energy, K = 1/2 x I x ω^2

K = 0.5 x (F^2 x R^2 x t^2) / I

K = 0.5 x 50 x 50 x 1.5 x 1.5 x 3 x 3 / (0.5 x 81.63 x 1.5 x 1.5)

K = 275.6 J