Question

A particle is released from the rest at a height of 100m. Find the distance it falls in first 2s and the next 2s respectively. (g = 9.8 m/s)
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Answer 1

We know that ,

s=ut+1/2at²

Here u=0

a=g=9.8 m/s²

t= 2 second

So, distance covered in 2 second=0+1/2×9.8×2²=19.6 m

And distance covered in 4 second=0+1/2×9.8×4²=78.4 m

The particle covers the distance in first 2 second is=19.6 m( i.e. the height is=100-19.6=80.4 m)

It covers the distance in next 2 second=78.4-19.6=68.8 m