Question

A rock falls from a cliff and travels downward for 6 seconds before striking the ground. How fast was the rock moving when it hits the ground? Assume there is no air resistance.

Answer 1

Given parameters:

duration of fall  = 6s

Unknown:

Speed of the rock before it hits the ground  = ?

Solution:

To solve this problem, we apply one of the appropriate motion equations;

           V = u + gt

Where V is the final velocity

           u is the initial velocity

           t is the time taken

           g is the acceleration due to gravity  = 9.8m/s²

The initial velocity is 0;

     So;

              V = gt

Input the parameters and solve for V;

                V = 9.8 x 6  = 58.8m/s

The velocity before hitting the ground is 58.8m/s