11Tension = T
T - mg = ma
20000 - (500 +80X)10 = (500 +80X)2
20000 = 6000 + 960X
14000 = 960X
X = 14000/9600
X = 14.533
Since ppl can only be integers Therefore answer is 14
Mr X of mass 80 kg enters a lift and selects the floor he wants. The lift now acc upward at 2 m/s2 for 2 sec and then moves with const velocity. As a lift approaches his floor, it decelerates at the same rateas it is previously accelerates. If the lift cable can safely withstand a tension of 20000 N and the lift itself has a mass of 500 kg, show that only 14 Mr X's could it safely carry one at a time.
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1 Answers
11