A 3.5kg toy falls from 3m to 2m. What is the change in GPE?

The diagram shows a series of volcanic island and a hot spot determine the direction of movement of the tectonic plate that for the island

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Amachinist turns the power on to a grinding wheel, at rest, at time t = 0 s. the wheel accelerates uniformly for 10 s and reaches the operating angular velocity of 96 rad/s. the wheel is run at that angular velocity for 40 s and then power is shut off. the wheel slows down uniformly at 1.5 rad/s2 until the wheel stops. in this situation, the time interval of deceleration is closest to: