Question

What average horsepower is developed by a an $80kg$ man while climbing in $10s$ flight of stair that rises $6m$ vertically?

• A. $0.63hp$
• B. $1.26hp$
• C. $1.8hp$
• D. $2.1hp$

Answer 1

The correct option is A $0.63hp$

Given,

$m=80kg$

$h=6m$

$t=10s$ Time of flight to rise height h

Take $g=10m/s^2$

The energy required to work against gravity,

$E=mgh=80\times 10\times 6$

$E=4800J$

The average power generated, $P=\frac{E}{t}$

$P=\frac{4800}{10}=480W$

As, we know that, $1hp=746W$

$1W=\frac{1}{746}hp$

$480W=\frac{480}{746}=0.6434hp$

The correct option is A.