Question

3. How long will it take a ball to reach the ground if it falls from a cliff 25 m tall (starting from rest)? What if the ball were given an initial horizontal velocity of 5 m/s? please help,thanks​

Answer 1

2.26 s

Step-by-step explanation:

Let's take down to be positive.

Given (in the y direction):

Δy = 25 m

v₀ = 0 m/s

a = 9.8 m/s²

Find: t

Δy = v₀ t + ½ at²

25 m = (0 m/s) t + ½ (9.8 m/s²) t²

25 = 4.9t²

t = 2.26 s

If the ball instead had an initial horizontal velocity of 5 m/s, its initial vertical velocity is still 0 m/s. So the time to fall is still 2.26 s.