3) A solid, uniform, horizontal disk with a diameter of 2.0 m and a mass of 4.0 kg freely rotates at 36 rpm about a vertical axis through its center. A small 0.50-kg stone is suddenly dropped onto the disk and sticks to the disk at a distance of 80 cm from the axis of rotation. The figure shows before and after views. (a) Before the stone fell, what was the moment of inertia of the disk about its central axis? (b) After the stone stuck, what was the moment of inertia of the system about the same axis? (c) What is the angular velocity of the disk (in rpm) after the stone fell onto the disk?4) a) A cyclist exerts a downward force on a bicycle pedal as shown below. Find the torque about O. 0.800 m O 60.09 40.0 Nb) In opening a door, a 30.0 N force is applied as shown below. Find the torque produced by this force with respect to point O. 17.0 cm 30.0 N O 45.0 5) A centrifuge rotor is accelerated for 30 s from rest to 20, 000 rpm (revolutions per minute). (a) What is its average angular acceleration? (b) Through how many revolutions has the centrifuge rotor turned during its acceleration period, assuming constant angular acceleration