Question

The ratio of the weight of a man in a stationary lift and when it is moving downward with uniform acceleration ${}^{\prime }{a}^{\prime }$ is $3:2$. The value of ${}^{\prime }{a}^{\prime }$ is ($g=$acceleration due to gravity of the earth)

• A. $\frac{3}{2}g$
• B. $\frac{g}{3}$
• C. $\frac{2}{3}g$
• D. $g$

Answer 1

The correct option is B $\frac{g}{3}$

As we know,

Weight of the man in lift $W_1=mg$

Weight in it when moving downwards with uniform acceleration $W_2=mg-ma$

We have given that,

$\frac{W_1}{W_2}=\frac{3}{2}$

$\frac{mg}{mg-ma}=\frac{3}{2}$

$\frac{g}{g-a}=\frac{3}{2}$

$2g=3g-3a$

$g=3a$

$a=\frac{g}{3}$