Question

12.the answer is 2 option..no spamming !!?

Answer 1

as the vertical component of velocity is equal to the horizontal component of velocity after time t

then,

u cosx =u sinx-gt

gt=u sinx-u cosx

t=u/g(sinx-cosx)

is angle theta is less than 45 degrees then the time will come out to be negative

hence in the question it is mentioned that the angle theta must be greater than 45 degree only then the time will be positive

I hope this helps ( ╹▽╹ )