A particle of mass `m` is projected at an angle `alpha` to the horizontal with an initial velocity `u`. The work done by gravity during the time it reaches its highest point is

A particle of mass m is projected with speed u at angle theta with horizontal from ground. The work done by gravity on it during its upward motion is

A paricle of mass m is projected with a velocity u at angle alpha with the horizontal. Work done by gravity during its descent from its highest point to, the position where its velocity vector makes an angle (alpha)/2 with the horizontal is

A particle of mass.m. is projected with a velocity .u. at an angle . theta . with the horizontal. Work done by gravity during its descent from its highest point to a point which is at half the maximum height is

A particle of mass m is projected with velocity v at an angle theta with the horizontal. Find its angular momentum about the point of projection when it is at the highest point of its trajectory.

A particle of mass m is projected with velocity v at an angle theta with the horizontal. Find its angular momentum about the point of projection when it is at the highest point of its trajectory.