Question

An elevator is accelerating upwards with an acceleration $6m/s^2$. Inside it a person of mass $50kg$ is standing on a weighing machine which is kept on an inclined plane having angle of inclination ${60}^{\circ }$. The reading of the weighing machine is

• A. $80kg$
• B. $50kg$
• C. $160kg$
• D. $40kg$

Answer 1

The correct option is D $40kg$

Draw FBD for the person.



Find the reading of the weighing machine.


Given, mass of the person,$m=50kg$
Acceleration of the elevator,$a=6m/s^2$
As the person is inside the lift (accelerated frame),so pseudo force will act on it.
So, $N=m(g+a)\cos {60}^{\circ }$

$N=50(10+6)\left(\frac{1}{2}\right)$

$N=400N$
So,reading of the weighing machine $=\frac{N}{g}$

$=\frac{400}{10}=40kg$

Final answer :$\left(A\right)$