An object is projected from a height of 80 m above the ground with a velocity of 40ms-1 at an angle of 30^\circ to the horizontal. The time of flight [ g ≈ 10m/s\(^2\)
A
8 s
B
4 s
C
16 s
D
10 s
Verified Correct Answer: B.
Physical Principles & Numerical Solution
for a body projected at an angle \theta to the horizontal, the time of the flight is given by T = (2u sin \theta)/g =(2x 40)x sin (30)/10 =(2 x 40) x (0.5)/10 = 4.0secs.
Source: Myschool Past Questions Archive (Record #13681)