Question

A body of mass $2\text{kg}$ is hung on a spring balance mounted vertically in a lift. If the lift moves up with an acceleration equal to the acceleration due to gravity, the reading on the spring balance will be

• A. $2\text{kg}$
• B. $2\times g\text{kg}$
• C. $4\times g\text{kg}$
• D. $4\text{kg}$

Answer 1

The correct option is D $4\text{kg}$

Suppose $F$ is reading of spring balance. Then,
$F-2g=2g$
or $F=4g$
So it is $4\text{kg.wt}$ or $4g\text{-Newton}$.