A stone on a bridge on a river falls into the river. If it takes 3 seconds to reach the surface of water, find (i) velocity of the stone at the instant it touches the surface of water (ii) the height of the bridge from the surface of water.

Explanation

Data : `u=0m//s, t=3s,`
`g=9.8m//s^(2), v=? , h = ?`
(i) `v=u+g t=0m//s+9.8m//s^(2)xx3s`
= 29.4m/s ltbrrgt The velocity of the stone at the instant it touches the surface of water = 29.4 m/s
(ii) `s=ut+(1)/(2)g t^(2)`
`=0m//sxx3s+(1)/(2)(9.8m//s^(2))(3s)^(2)`
`=4.9xx9m=44.1m`
`therefore ` The height of the bridge from the surface of water = 44.1 m.