Question

how long will a stone take to fall on to Ground from top of a building 80 metre high what will be the velocity of the stone on reaching the ground (g=10m/s²)​

Answer 1

Answer:

$s = ut + \frac{1}{2} a \: t {}^{2} \\ 80 = 0.t + 0.5 \times 10 \times t {}^{2} \\ 160 = t {}^{2} \\ t = \sqrt{160} \\ t = 4 \sqrt{10} \: sec$

v=u+at

v=0+10(4√10)

v=40√10. m/sec