Diver curls his bosy when diving so that he can perform some quick somersaults. This is because:

Explanation

A) By the law of conservation of angular momentum, the total angular momentum of the diver will stay the same irrespective of the way the diver curls his body. Therefore, A is incorrect since his angular momentum cannot increase. B) When the diver is curling his body, you can think of him as trying to form a tighter, smaller circle. Since the imaginary circle's size is decreasing, the effective radius of the will also decreases, so B is incorrect. C) By the law of conservation of angular momentum, the total angular momentum of the diver will stay the same irrespective of the way the diver curls his body. Therefore, C is incorrect since his angular momentum cannot decrease. D) By elimination, D must be correct. Since the diver is performing somersaults faster, he is rotating around the circle faster. Therefore, his speed while rotating around the circle (i.e. the angular speed) increases, so D is the correct answer.