# A projectile is thrown with speed 40 ms-1 at angle ? from horizontal. It is found that projectile as at same height at 1s and 3s. What is the angle of projection?

Aastha
13 Points
3 years ago
T=2usin¢/g :time of flight is given by this formula
Sin ¢ =gT/u
Now,
Sin¢=2*40/10=1/2
¢=30°
Putting the value of ¢in tan we get,
Tan 30°=1/√3
¢=tan-1(1/√3)

Khimraj
3007 Points
3 years ago
time period = 2*2 = 4 sec
so 2usin$\Theta$/g = 4
sin$\Theta$ = 40/80 = ½
so $\Theta$ = 30 degree
Hope it clears..........................