Question

A 60 kg man runs up a staircase in 12 seconds while a 50 kg man runs up the same staircase in 11 seconds, the ratio of the rate of doing their work is

• A. 6:5
• B. 12:11
• C. 11:10
• D. 10:11

Answer 1

Answer: (C)

11:10

It is known that Rate of work done=power=Work done/time

Here$P=\frac{mgh}{t}$

$P\propto \frac{m}{t}$

$\Rightarrow \frac{P_1}{P_2}=\frac{m_1}{m_2}\times \frac{t_2}{t_1}$

$\therefore \frac{P_1}{P_2}=\frac{60}{50}\times \frac{11}{12}=\frac{11}{10}$