Question

Ball is dropped from a bridge of 122.5 metre above a river. After the ball has been falling for two seconds, a second ball is thrown straight down after it. Initial velocity of second ball so that both hit the water at the same time is (1) 49 m/s (2) 55.5 m/s (3) 26.1 m/s (4) 9.8 m/s

Answer 1

ut+at^2/2=ut+at^2/2

u3+9.8*3*3/2=9.8*5*5/2

u3+4.9*9=4.9*25

u3+44.1=122.5

3u=78.4

u=78.4/3=26.1

26.1 is answer