A plank rests on two supports that exert upward forces of 14N and 18N. find the weight of the plank.

32

Explanation:

Up forces and Down forces must be equal if the object is balanced

For this question

down force is weight of the plank

up forces is 14 and 18

14+18=Weight of plank

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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