A particle is projected from a point on the level ground and its height is `h` when at horizontal distances `a and 2 a` from its point of projection. Find the velocity of projection.

A particle is projected from the ground with velocity u making an angle theta with the horizontal. At half of its maximum heights,

A particle is projected from the ground with some initial velocity making an angle of 45^(@) with the horizontal. It reaches a height of 7.5 m above the ground while it travels a horzontal distance of 10 m from the point of projection . Find the initial speed of projection ( g = 10 m//s^(2) ) .