Show that time of ascent of a vertically projected body is equal to time of descent.

A body is pushed up on a rough inclined plane making an angle 30^(@) to the horizontal. If its time of ascent on the plane is half the time of its descent. Find coefficient of friction between the body and the inclined plane.

(A) : The time of ascent for a body projected to move up a rough inclined plane is less than the time of descent. (R ) : The retardation for upward motion is more than the acceleration for down motion on rough inclined plane.