Question

A person of mass $60\text{kg}$ is in a lift. The change in the apparent weight of the person, when the lift accelerates up with an acceleration of $2{\text{m/s}}^2$ and then down with an acceleration of $2{\text{m/s}}^2$ is

• A. $120\text{N}$
• B. $240\text{N}$
• C. $480\text{N}$
• D. $720\text{N}$

Answer 1

The correct option is B $240\text{N}$

When lift is moving up apparent weight $W_{up}=m(g+a)=W_1$
When lift is moving down
apparent weight $W_{down}=m(g-a)=W_2$
Now change in $W_1-W_2=2ma$
$=2\times 60\times 2$
$=240\text{N}$