Physics

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Imagine that if you drop an apple from a certain height, its final speed is 20 m/s when it reaches the ground. If you throw the apple vertically downward from the same height with an initial speed of 20 m/s, what will be its final speed?

I tried 2mgh=1/2mv^2 so that the mass would cancel out and then i solved for h and used that number in the equation v^2=V(o)^2+2a(h) and I am not getting the correct answer... any help would be greatly appreciated! thank you

  • Physics -

    v=gt
    t=v/g =20/9.8 =2.04 s
    h=gt²/2 =9.8•2.04²/2 =20.4 m
    h=(v²-v₀²)/2g
    v=sqrt{2gh+ v₀²} =sqrt{2•9.8•20.4 +20²}=
    =28.3 m/s

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