Question

A man weighing $70$ kg climb staircase with a speed of $10$ steps/min.If the height of each step is $20$ cm, the power consumed is

• A. $3/7$ W
• B. $7/3$ W
• C. $70/3$ W
• D. $140$ W

Answer 1

The correct option is C $70/3$ W

Given Mass of man, $m=70kg$

Total height covered in $1$ min =$10\times 20cm=200cm=2m$

Total energy consumed in $1$ min $=mgh=70\times 10\times 2=1400J$

Power consumed,$=\frac{Energy}{time}=\frac{1400}{60}=\frac{70}{3}W$