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zim70094
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Homework Statement
Ball A is thrown straight upward and returns to its original level in 2 seconds. Ball B is thrown at a 40 degree angle above the horizontal and also returns to its original level in 2 seconds. What is the initial speed of each ball.
Homework Equations
ΔV=at
ΔX=Vit+1/2at^2
v^2-Vi^2=2a(ΔX)
ΔX=1/2(V+Vi)t
The Attempt at a Solution
for ball A I replaced acceleration with gravity and tried to find Vi with the first equation a=-9.81 and t=2s but I didn't know what to do with Vf. I thought maybe it was zero and came up with 19.62 m/s but i know that's not right.
for ball b i know that Vi in the y direction is Visinθ and x direction is Vicosθ but I'm not positive how to apply this information. I think I may have to use my knowledge of vectors too but I'm not sure. for example i think I use V=square root of (Vix^2 + Viy^2)