Question

a stone is dropped from a cliff calculate its speed after it has fallen 80m.(g=10m/s to the power 2 )

Answer 1

hey the answer is 40m/s

Answer 2

Given,

Distance fell by the stone, $s = 80m$

$g = 10m/s^{2}$

To Find,

The speed of the stone after it has fallen =?

Solution,

We can solve the question using the following steps:

According to the third Equation of Motion,

$v^{2} = u^{2} + 2gs$

Here,

$v =$ final velocity

$u =$ initial velocity

$s =$ distance travelled

From the question,

$u = 0$

$s = 80m$

$v^{2} = 0^{2} + 2(10)(80)$

$v^{2} = 1600$

$v =$ ±$40 m/s$

Hence, its speed after it has fallen will be 40m/s.