Answer:
Option 2
Explanation:
Weight of the box is being acted downwards due to gravity
However, based on Newton's third law (for every action (force) in nature there is an equal and opposite reaction), an equal force will act on the box by the table
Answer:

Explanation:
Given:
angular speed of rotation of friction-less platform, 
moment of inertia with extended weight, 
moment of inertia with contracted weight, 
<u>Now we use the law of conservation of angular momentum:</u>



The angular speed becomes faster as the mass is contracted radially near to the axis of rotation.
Between magnitude of the average 4sec