Question
A ball is thrown from the location (x_0, y_0 )=(0,0) of a horizontal playground with an initial speed v_0 at an angle _0 from the +x-direction. The ball is to be hit by a stone, which is thrown at the same time from the location (x_1, y_1 )=(L, 0). The stone is thrown at an angle (180- _1 ) from the +x-direction with a suitable initial speed. For a fixed v_0, when ( _0, _1 )= (45^ , 45^ ), the stone hits the ball after time T_1, and when ( _0, _1 )= (60^ , 30^ ), it hits the ball after time T_2. In such a case, (T_1 / T_2 )^2 is _______ .