Viresh kumar
Last Activity: 7 Years ago
Solution to the question is very easy,just think logically...
Particle is thrown at angle 30 with horizontal...
AT the time when it’s velocity is perpendicular to initial velocity,its velocity will be making an angle 120 with the positive x-axis..
THen,by using v=u+at,
20.sin120=20.sin30 – 10t (a=-g = -10)
-10.31/2 = 10 – 10t
t= 1 + 31/2
t= 2.73 s