Question

5.  A disc A of mass m sliding over a smooth horizontal surface with velocity v experiences a perfectly elastic collision with a smooth stationary wall at a point O. The angle between the motion direction of the disc and normal to the wall is equal to α. Find:

(a) The point relative to which the angular momentum L of the disc remains constant in this process;

(b) The magnitude of the increment of the vector of the disc’s angular momentum relative to the point O’ which is located in the plane of the disc’s motion at the distance l from the point O.

Answer 1

b is the largest answer

Answer 2

b is the correct option