Question

seema steps off a 15m high cliff overlooking the lake and free falls until hitting the water. A. how long will it take them to hit the ground? b. how fast will it they be moving when they hit the water ?​

Answer 1

Explanation:

1. Using the 1st equation of motion

$s = ut + \frac{1}{2} at {}^{2}$

we get ,

15 = 0.t + 1/2 × 10 × t^2

=> 15 = 5 t^2

=> t^2 = 3

=> t = √3 = 1.71 s

2. Using the 3rd equation of motion,

${v}^{2} = {u}^{2} + 2as$

we get ,

v^2 = 0^2 + 2×10×15

=> v^2 = 300

=> v = 10√3 = 17.1 m/s