23) A ball was thrown straight up into the air at 50. m/s, how fast was it going 2.2 seconds later? (acceleration = g = -9.8 m/s2)

-9.8m/s^2 x 2.2 = -21.56m/s^2 50m/s - 21.56m/s^2 = 28.44m/s

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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