Disc Brake में क्यों होते हैं छेद?Why there is holes in disc brake? #shorts

A circular hole is cut from a disc of radius 6 cm in such a way that the radius of the hole is 1 cm and the centre of 3 cm from the centre of the disc. The distance of the centre of mass of the remaining part from the centre of the original disc is

A uniform disc (of mass M and radius a ) has a hole (of radius b ) drilled through it. The centre of the hole is at a distance c from the centre of the original disc. What is the moment of inertia of the disc about an axis through the centre of the disc and perpendicular to its plane ?

Why is it difficult to move a bike with its brakes on ?

A homogeneous disc of weight W and radius R rotates about the vertical axis OZ, the initial angular velocity being omega_(0) . During the motion, the brake block A is pressed to the disc,with a radial force N for t_(0) seconds and the disc comes to rest because of friction. Find the coefficient of friction.

A disc of radius r is cut from a larger disc of radius 4r in such a way that the edge of the hole touches the edge of the disc. The centre of mass of the residual disc will be a distance from centre of larger disc :-