Question

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

Answer 1

From the definition of the time of flight,

0=usinq*T-0.5gT^2

or, 5T= 40 sinq

or, 5*4=40sinq

or, 0.5= sinq

Hence q= 30 degrees.

So the angle of projection is certainly 30 degrees.

Answer 2

Answer:Theta = 30°

Explanation:

T = t1 + t2

2u sin Φ

-------------- = 1 + 3

g

2 x 40 sin Φ

------------------ = 4

10

SinΦ = 1/ 2

Φ = 30°