A tennis ball projected at an angle 0 attains a range R = 78. If the velocity imparted to the ball by the racket is 30 ms\(^{-1}\), calculate O. [ g = 10 ms\(^{-2}\)]
Explanation
R = \(\frac{U^2 sin 2\theta}{g}\), 78 = \(\frac{30^2 sin 2\theta}{10}\)
\(sin2\theta = \frac{780}{900}\) = 0.8667, \(2\theta = sin^{-1}0.8667 = 60^o\)
\(\theta \frac{60^o}{2} = 30^o\)