Question

The mass of a body indicated by a weighing machine in a lift at rest is found to be $m$. If the lift is going up with an acceleration $a$, then the new reading shown by the scale will be

• A. $m(1-\frac{a}{g})$
• B. $m(1+\frac{a}{g})$
• C. $m$
• D. Zero

Answer 1

The correct option is B $m(1+\frac{a}{g})$

When lift is moving up
Net Normal reaction is
$N=m(g+a)$
mass measured $=\frac{N}{g}=\frac{m(g+a)}{g}$
$=m(1+\frac{a}{g})$