Question

A lift is going up. The total mass of the lift and the passenger is 1500 kg. The variation in the speed of the lift is as given in the graph. The tension in the rope pulling the lift at t = 11th sec will be

• A. 17400 N
• B. 14700 N
• C. 12000 N
• D. Zero

Answer 1

Answer: (C)

12000 N

Answer 2

At 11th second lift is moving upward with acceleration

$a = \frac { 0 - 3.6 } { 2 } = - 1.8 \mathrm {~m} / \mathrm { s } ^ { 2 }$

Tension in rope, $T = m ( g - a )$

$= 1500 ( 9.8 - 1.8 )$ = 12000 N