Question

An elevator of mass $500\, kg$ is ascending upwards with a constant acceleration $a =2 \, m / s ^{2}$. What is the work done by the tension in the elevator cable during its climb by $12 \, m$ ?
$\left(\right.$ Take $\left.g =10 \, m / s ^{2}\right)$

• A. $36\, kJ$
• B. $48\, kJ$
• C. $72\, kJ$
• D. $100\, kJ$

Answer 1

Answer: (C)

Mass of elevator, $m=500 \,kg$
Acceleration of elevator, $a=2 \,ms ^{-2}$ (upward)
When elevator is going upward,
then tension in the elevator cable,
$T=m(g+a)=500(10+2)=6000 \,N$
$\therefore $ Work done by the tension force in the cable,
$W=T \times s=6000 \times 12$
$[\because$ given $s=12 \,m ]$
$=72000\, J =72 \,kJ$