From an inclined palne two particles `P,Q` are projected with same speed at same angle `theta`,one up and other down the plane as shown in figure.Which of the following statement(s) is/are correct ?

Options

A. The particles will collide the plane with same speed
B. The times of flight of each particle are same
C. Both particles strike the plane perpendicularly
D. The particles will collide in mid air if projected simultaneuosly and time of flight of each particle is less than the time of collision.

Answer

B, D

Explanation

`T_(1)= T_(2)`
Further acceleration of both the particles is `g` downwards.Therefore, relative acceleration between the two is zero or relative motion between the two is uniform.Now relative velocity of `P` with respect to `Q` is towards `PQ`.Therefore, collision will take place between the two in mid air.