Clue 1: what are the units of U in Equation 3? Do these units suggest how calculating U might permit you to calculate kinetic energy?

Clue 2: Note that the acceleration of our chunk of rock in space is independent of the mass of that rock. We can write

(5)

where F is the force of gravity at any instant in time, g the strength of the gravitational field, m the mass of the object in that field, and a the acceleration of the object.

Clue 3: What are the units of energy, and what do you have to multiply units of U by in order to get units identical to those of energy? What does Equation 1 suggest?

Ignoring the effects of the atmosphere, how fast does is meteorite moving when it hits the earth’s surface?

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