define moment of inertia. write any two factors on which it depends. when the diver leaves the diving board,why he bring his hand and feet closer together in order to make a somersault?

(1)

We know that moment of inertia (I) is given as

I = mr²

here 'm' is the mass and 'r' is the radius.

so, the moment of inertia depends upon

(a) the location of the axis of rotation and

(b) the distribution of mass inside the body 

(2)

According to law of conservation of angular momentum the rate of spin of the diver increases as he/she draws their arms and legs inwards. This is because the radial distance decreases which increases the angular speed as mass stays constant.