1. The problem statement, all variables and given/known data There is a projectile which is launched at point "o" and land at "B".It was thrown with 20m/s with angle of 53 degree.Take g=10 m/s^2 sin theta=0.8 and cos theta=0.6 Find the time at which magnitude of x component of velocity of projectile is twice the magnitude of y component of velocity. 2. Relevant equations v sub x =u sub x +a sub x t u sub x=initial velocity in x-direction i.e u cos theta =16 m/s v sub x =velocity in x direction at time t. v sub y =velocity in y direction at time t v sub y =u sin theta +(- 10 t) 3. The attempt at a solution v sub x=2 (u sin theta +(- 10 t) but v sub x=u cos theta (as acceleration in x i.e horizontal direction is zero. so,u cos theta =2 (u sin theta - 10 t) putting given values give t=1 sec. But in book two answer are given t=1 sec and t=2.2 sec. How I can get t=2.2 s ?