I need help with this problem in depth please

Question

A projectile is shot from the edge of a cliff 125m above ground level with an initial speed of 65 m/s at an angle of 0 above the horizontal. 

a) Determine the time taken by the projectile to hit ground level.

b) Determine the distance the projectile travels measured from the base of the cliff to the landing point.

Answer 1

Wee vertically we can use s = ut + 0.5 at²

u = initial vertical sped = 0 as it was fired horizontally

a = 9.81 m/s/s = acceleration downwards due to gravity

s = 125 m

giving t = √ 6.37 = 2.52 s

Horizontal speed is constant (no force in horizontal direction) = 65 m/s

So distance = 2.52 x 65 = 163.8 m