Question

A man $M_1$ of mass $80kg$ runs up a staircase in $15s$. Another man $M_2$ also of mass $80kg$ runs up the staircase in $20s$. The ratio of the power developed by them will be:

• A. 1
• B. 4/3
• C. 16/9
• D. none.

Answer 1

The correct option is B 4/3

$Power=\frac{Work}{Time}$

Since, work done is same in both the cases because both the man are of same mass and climb same height. Only difference is of Time-

$P1=\frac{W}{15}andP2=\frac{W}{20}$

$So,\frac{P1}{P2}=\frac{\frac{W}{15}}{\frac{W}{20}}=\frac{\frac{1}{15}}{\frac{1}{20}}=\frac{20}{15}=\frac{4}{3}$