A particle is projected horizontally at 10 ms\(^{-1}\) from a height of 45m. Calculate the horizontal distance covered by the particle before hitting the ground. [g = 10ms\(^{-1}\)]
Horizontal projectile
Horizontal velocity \(u = 10\ \text{m s}^{-1}\), height \(h = 45\ \text{m}\), \(g = 10\ \text{m s}^{-2}\).
Time to fall (vertical motion, initial vertical velocity zero):
\(h = \tfrac{1}{2}g t^{2} \Rightarrow 45 = \tfrac{1}{2}\times10\times t^{2} = 5t^{2}\).
\(t^{2} = 9 \Rightarrow t = 3\ \text{s}\).
Horizontal distance (range): \(R = u\,t = 10\times3 = 30\ \text{m}\).
The particle covers a horizontal distance of 30 m before hitting the ground.