Question

A person of mass $60kg$ inside a lift of mass $940kg$ presses the button on control panel. The lift starts moving upwards with an acceleration of 1 $m/s^2$. If $g=10m/s^2$ , the tension in the supporting cable is

• A. $660N$
• B. $10000N$
• C. $10340N$
• D. $11000N$

Answer 1

The correct option is D $11000N$

Mass of the person, $m=60kg$
Mass of lift, $M=940kg$, $a=1m/s^2$, $g=10m/s^2$
Let $T$ be the tension in the supporting cable
$T-(M+m)g=(M+m)aT=(M+m)(a+g)=(940+60)(1+10)=11000N$