Answer:
255.34 J
Step-by-step explanation:
Given,
Weight of disk = 805 N
radius = 1.47 m
Force applied by the child = 49 N
time = 2.95 s
KE = ?
mass of the disk

Moment of inertia of the disk


Torque on the child

Angular acceleration

So, angular speed at t = 2.95 s

Now, KE of the merry go round

Hence, the Kinetic energy of the merry go round = 255.34 J