Question
Tue September 18, 2012 By:
 

a ball dropped from height of 20m. A second ball is thrown downward from the same height after one second later with initial velocity u. If both balls reach the ground at same time calculate the initial velocity of second ball

Expert Reply
Tue September 18, 2012
H = 20m
Time taken for the first ball to come down: T = (2gH)^1/2
T = 20s
 
let the initial velocity be u
not using the second equation of motion:
 
H = uT + 1/2gT2
we can find u
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