(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A boy release ball A from height 5m from ground at the same time other boy throw ball B vertically upward to exactly strike ball A. When ball B released it was 1m from ground find minimum initial velocity of ball b. Given g=10m/s^2

a) 2m/s b) 3m/s c) 4m/s d) 5m/s

2. Relevant equations

x (t) = v0t+1/2at^2

3. The attempt at a solution

From the problem distance between each ball is 4m when it was released and both was released at same time so when it strike each other time must be equal

Then i let x be the distance ball A travel and 4-x be distance ball B travel so i got.

x=1/2gt^2 = 5t^2 since ball A was released it has no initial velocity

and 4-x=v0t-1/2gt^2=v0t-5t^2

Solve for both I got ut =4 then I stuck here then I substitude value from choice and got 5 (the exact is about 4.4) so is there any real way to solve this

P.S. I try using energy conservation and end up with 0=0 all time.

Sorry if the problem look weird since I translate it from my own language

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# Homework Help: Initial velocity of ball B hit a free falling ball A

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