Question

A child throws a penny straight down into a wishing well. The penny's initial speed is 2 m/s. If the penny takes 3 seconds to hit the water, how deep is the well?

Answer 1

$L = v_0\cdot t + \frac{1}{2}gt^2$

In this case v_0 = 2 m/s and t=2
Putting everything in will be

$L = 2\cdot 3 + \frac{1}{2}\cdot9.82\cdot 2^2 = 6 + 19.64 = 26$

So the answer is 26 m.