# physics

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an object of mass 10kg is dropped from a 20 m cliff. what is the velocity just before the object strikes the ground?

• physics -

v = Vo + a t = -9.8 t
z = Zo + Vo t + (1/2) a t^2
0 = 20 + 0 + 4.9 t^2
so
t = sqrt (20/4.9)
and
v = -9.8 sqrt (20.4.9)

• physics -

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