WAEC - Physics (1993 - No. 9)
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 θ. (g = 10 ms\(^{-2}\)).
0o
30o
45o
60o
90o
설명
T = \(\frac{2u sin θ}{g}\)
sin θ = \(\frac{Tg}{2u}\)
sin θ = \(\frac{10 \times 10}{2 \times 100}\) = 0.5
θ = sin\(^{- 0.5}\) = 30º
\(\theta\)\(_{horizontal}\) = 30º
But \(\theta\)\(_{vertical}\) = 90º - 30º = 60º