An object is projected with a velocity of 100 ms\(^{-1}\) from the ground level at an angle \(\theta\) to the vertical. If the total time of flight of the projectile is 10 s, calculate ΞΈ. (g = 10 ms\(^{-2}\)).
- 0o
- 30o
- 45o
-
60o
- 90o
The correct answer is: D
Explanation
T = \(\frac{2u sin ΞΈ}{g}\)
sin ΞΈ = \(\frac{Tg}{2u}\)
sin ΞΈ = \(\frac{10 \times 10}{2 \times 100}\) = 0.5
ΞΈ = sin\(^{- 0.5}\) = 30ΒΊ
\(\theta\)\(_{horizontal}\) = 30ΒΊ
But \(\theta\)\(_{vertical}\) = 90ΒΊ - 30ΒΊ = 60ΒΊ