Question

A body of mass $50kg$ is suspended using a spring balance inside a lift at rest. If the lift starts falling freely, the reading of the spring balance is

• A. $=0$
• B. $<50kg$
• C. $=50kg$
• D. $>50kg$

Answer 1

The correct option is A $=0$

As the lift is freely falling, thus its acceleration in down ward direction $a=g$

Let the mass of the body be $m$ and force acting on it due to spring be $F$.

Writing equation of motion for the body : $ma=mg-F$

Or $mg=mg-F$

$⟹$ $F=0$

Thus no force is acting on the body due to spring, so the reading of the spring balance is zero.