Question

A stone was dropped freely in a river flowing down a bridge. the stone takes 2 seconds in touching the water surface. the height of the bridge is- 1) 9.8 m 2) 19.6 m 3) 39.2 m 4) data inadequate

Answer 1

1) 9.8 m is the answer

Answer 2

s=h therfore, freely falling means u=0 so nlm 2nd {s=ut+1/2at^2} u is 0 so {s=1/2at^2} so putting value we get ans S=H=19.6 m