Question

A rock falls from a cliff. What is its displacement after 2 seconds, in m?

Answer 1

A rock falls from a cliff. 19.6 m is its displacement after 2 seconds

Answer: 19.6 m

Explanation:

The rock falling from the cliff falls under the effect of gravity. And as it falls, the initial velocity is zero. To calculate the displacement of the rock which fell from the cliff, after 2 seconds, use the equation of motion, as follows,

We know that 2nd equation of motion,

`s=u x t+(1)/(2) a x t^(2)`

Given that t=2 sec and u=0. Putting the values into the equation, we get,

`s = (0 * 2)+(1)/(2)(9.8 * 2 * 2) = 9.8 * 2 = 19.6 m`