Answer:
F = 150 N
Explanation:
Torque being applied by parent
= F x r
where F is force applied tangentially and r is point of application of force from axis of rotation ( center )
given torque = 240 Nm
r = 1.6 m
F x r = 240
F x 1.6 = 240
F = 150 N
So a force of 150 N is applied by the parent to achieve the given torque.
This force will also be applied by the merry - go- around on the parent as reaction force according to Newton's third law. The parent will not be pushed back by this force because he is standing on a rough surface . Friction of surface will help him remain stationary on the ground.