Question

A person of mass $50kg$ stands on a weighing scale on a lift. If the lift is descending with a downward acceleration of $9m/s^2$, what would be the reading of the weighing scale?$(g=10m/s^2)$

Answer 1

Step 1: Find the apparent weight of the person.

Hint: When the lift accelerates downwards, the man's apparent weight within it diminishes.

Given, mass of the person, $m=50kg$

Descending acceleration,$a=9m/s^2$

Acceleration due to gravity, $g=10m/s^2$

As the lift is descending with acceleration a,the apparent weight of a body of mass m decreases on weighting scale is

$W=R=(mg-ma)=m(g-a)$

$=50(10-9)=50N$

Step 2: Find reading on the weighing scale.
Reading of the weighing scale
$=\frac{R}{g}=\frac{50}{10}=5Kg$


Final answer: $5kg$