Question

Forrest drops a rock from a bridge to the water below. The rock entered the water at a speed of 19.6 m/s. How long did it take the pebble to reach the water from the bridge? [s=d/t]

Answer 1

Answer:

It took the rock 2 seconds to get to the water from the bridge.

Explanation:

Since Forrest drops the rock, it means its initial velocity is zero, and because it is freely falling under the influence of gravity, after time $t$ it will gain a velocity $v$ of

$v = gt$,

solving for $t$ we get:

$t = \dfrac{v}{g}.$

Since in our case the velocity the rock gained was $v= 19.6m/s$ and the acceleration due to gravity is $g =9.8m/s^2$, we have

$t = \dfrac{19.6m/s}{9.8ms^{-2}}$

$\boxed{t =2s.}$

Thus, the time took the rock to reach the water from the bridge was 2 seconds.