Question

Two men with weights in the ratio 5 : 3 run up a staircase in times in the ratio 11 : 9. The ratio of power of first to that of second is

• A. $\frac{15}{11}$
• B. $\frac{11}{15}$
• C. $\frac{11}{9}$
• D. $\frac{9}{11}$

Answer 1

Answer: (A)

$\frac{15}{11}$

Answer 2

Power (P) = $\frac{mgh}{t}$ or $P \propto \frac{m}{t}$ ⇒ $\frac{P_{1}}{P_{2}} = \frac{m_{1}}{m_{2}}\frac{t_{2}}{t_{1}}$

$= \left( \frac{5}{3} \right)\left( \frac{9}{11} \right) = \frac{45}{33} = \frac{15}{11}$ (g and h are constants)