A projectile is thrown in upward direction making an angle of 60^ with the horizontal direction with a velocity of 150 ~ms ⁻¹ . Then, the time after which its inclination with horizontal is 45^ , is

Step-by-step solution

At the two points of the trajectory during projectile motion, the horizontal component of velocity is same. Then, 150 1 2 =v 1 2 v= 150 2 ~ms ⁻¹ Initially, u_y=u 60= 150 3 2 ~ms ⁻¹ Finally, v_y=v 45^ = 150 2 1 2 = 150 2 ~ms ⁻¹ But aligned v_y & =u_y+a_y t 150 2 & = 150 3 2 -10 t aligned array ll & 10 t= 150( 3 -1) 2 & t=7.5( 3 -1) s array