# A stone is dropped from a height of 20m. how long will it take to reach the ground. at what speed will it hit the ground?

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by arunabharoy2

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by arunabharoy2

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Use the formula s=ut +1/2g(t*t) and g=(v-u)/t

where s= 20 m

g=9.8m/s

u=0m/s

t=2s/g whole under root

where s= 20 m

g=9.8m/s

u=0m/s

t=2s/g whole under root

u=0

v=?

t=?

v²-u²=2gh

v²-o²=2*10m/s * 20m

v=√400

v=20m/s[velocity with which stone hit the ground]

v=u+gt

20=0+10*t

t=2s[time to reach the ground]