Question

A man raises a box of mass $50kg$ to a height of $2m$ in $2$ minutes, while another man raises the same box to the same height in $5$ minutes. Ratio of the power developed by them:

• A. $18000:7200$
• B. $2:5$
• C. $5:2$
• D. None of the above

Answer 1

Answer: (C)

$5:2$

$Work=F\times s$
$Force=m\times g$
In both the cases mass is equal and displacement is also equal.
$F=50\times 2=100N$
$Power=work/time$
$P\left(1st\right)=100/2=50$
$P\left(2nd\right)=100/5=20$
Hence both the powers are in the ratio of $50:20=5:2$.