# Physics - Free Fall

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A stone was thrown into the air and returned after 4.2 seconds.

a) At what speed was the stone thrown? (20.6) <- i got that right.

b) How high did the stone go? (21.6 m)

i don't know how to get b. what steps do i do?

• Physics - Free Fall -

The stone with an initial velocity, v, has a kinetic energy of (1/2)mv².

When at the top, velocity = 0, but the potential energy is mgh.

So equate energies to get
mgh = (1/2)mv²

Solve for h.

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