If we want to describe work, we must have (a) an action which causes no movement or reaction. (b)a force and a movement in the opposite direction of the force.(c) a force and a movement in the same direction as the force. (d)an action which causes movement and an opposite reaction.

The correct answer is C because why would you want to move the force away from the force. So therefore the answer C because you want to move the force to the force. Hope This Helps

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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photocells convert light energy to electricity