posted by ceasar .
A student of mass 80kg stands on a spring scale in an elevator.During the first 3seconds,starting from rest,the scale reads 80kg.Determine the velocity of the elevator at the end of the 3seconds,and the tension T in the supporting cable during the acceleration period.The total mass of the elevator,student and scale is 805kg.
if the scale reads a static weight of 80gk, the scale is not accelerating. So at the end of three seconds, the scale is at some constant velocity, it has not moved since the force never changed.
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