A ball is dropped from a bridge 122.5m above a river. After 2s, a second ball is thrown down after it. What must its initial velocity be so that both hit the water at the same time

Question

A ball is dropped from a bridge 122.5m above a river. After 2s, a second ball is thrown down after it. What must its initial velocity be so that both hit the water at the same time (A) 49 m/s (B) 55.5 m/s (C) 26.1 m/s (D) 9.8 m/s

Tardigrade Admin · Accepted Answer

For first ball h = ut + (1/2) gt2 For second ball h = ν (t - 2) + (1/2) g(t - 2)2

Q. A ball is dropped from a bridge 122.5m above a river. After 2s, a second ball is thrown down after it. What must its initial velocity be so that both hit the water at the same time

49 m/s

55.5 m/s

26.1 m/s

9.8 m/s

For first ball $h = u t + \frac{1}{2} g t^{2}$
For second ball $h = ν (t - 2) + \frac{1}{2} g (t - 2)^{2}$

Q. A ball is dropped from a bridge 122.5m above a river. After 2s, a second ball is thrown down after it. What must its initial velocity be so that both hit the water at the same time

49 m/s

55.5 m/s

26.1 m/s

9.8 m/s

For first ball h=ut+21​gt2 For second ball h=ν(t−2)+21​g(t−2)2

For first ball $h = u t + \frac{1}{2} g t^{2}$
For second ball $h = ν (t - 2) + \frac{1}{2} g (t - 2)^{2}$