Question

A pebble is thrown vertically upward from a bridge with an initial velocity of 4.9 m per second. It strikes the water after 2 seconds.If acceleration due to gravity is 9.8 m/s² 1) What is the height of the bridge 2) With what velocity does the pebble strike the water ?​

Answer 1

u is given = 4.9 , total time of flight = 2sec

applying , S = ut + at2/2 ,

S = H = ? , a=-g , u=+4.9m/s (upward)

putting these in above eq

H = 4.9*2 - 9.8(4)/2 = 9.8m