Two shells are fired from a cannot with a speed u each, at angles of `alpha` and `beta` respectively to the horizontal. The time interval between the shots is T. they collide in mid-air after time t from the first shot. Which of the following conditions must be satisfied ?

Options

A. `alpha gt B`
B. `t cos alpha = (t-T)cos beta`
C. `(t-T)cos alpha = t cos beta`
D. `(u sin alpha)t-1//2 g t^(2)=(u sin beta)(t-T)-(1//2)g(t-T)^(2)`

Answer

A, B, D