Joe forgot his homework at home. he runs home to get it. he accelerates from 0 to 15m/s in 5 seconds, runs at 15m/s for 50 seconds, and then slows down from 15m/s to a stop in 3 seconds. what is the acceleration

15m/s is his running speed which is faster than the around 28mph limit for humans and he stops in 3 seconds with division he slows down at a rate of 5 meters per second which means he loses 5m/s velocity per second so 5meters per second per second

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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