# physics

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A ball dropped from a sixth floor window accelerates at 10 m/s^2
After 2 seconds it hits the
ground. It bounces back with a
velocity of −15 m/s

1.find the height from which the ball was dropped.

2. How high did it bounce?

• physics -

h=gt²/2 = 10•2²/2=20 m
v=gt =10•2 =20 m/s
v=v₀-gt₁
v=0
t₁= v₀/g=15/10=1.5 s
h₁=v₀t₁-gt₁²/2 =
=15•1.5 -10•1.5²/2=11.25 m
a=Δv/Δt= (-15-20)/0.02= - 1750 m/s

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