Question

A person of mass $50kg$ carrying a load of $20kg$ walks up to a staircase. If the width and height of each step are $0.25m$ and $0.2m$ respectively, the work done by the man in walking up $20$ steps is, (g= $10m{s}^{-2}$)

• A. $1400J$
• B. $800J$
• C. $2000J$
• D. $2800J$

Answer 1

The correct option is D $2800J$

$Totalmassm=50+20=70$
$heighth=20\times 0.2=4m$
$workdone=mgh=70\times 10\times 4$
$=2800$