Question

A man will weigh more when

• A. lift accelerates upwards
• B. lift accelerates downwards
• C. lift descends freely
• D. lift is going down

Answer 1

Answer: (A)

When a lift accelerates upwards with uniform acceleration a
$\therefore$ Apparent weight of man $R=m(g+a)$

When a lift accelerates downwards with uniform acceleration a
$\therefore$ Apparent weight of man $R=m(g-a)$

When a lift descends freely
$\therefore$ Apparent weight of man $R=m(g-g)=0$
[since $a=g]$
When a lift is going down (without acceleration),
$\therefore$ Apparent weight of man $R=m(g-0)=mg$
[since $a=0]$
Hence, a man weigh more, when lift accelerates upwards