Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. How many $2.5\, kg$ bricks can man carry up a staircase $3.6\, m$ high in one hour if he works at an average rate of $9.8$ watt?

Work, Energy and Power

Solution:

Work done by man in one hour = power $\times$ time
$=9.8 \times 1 \times 60 \times 60 \, J$
Work done by man in raising one brick $=m g h$
$=2.5 \times 9.8 \times 3.6 \,J$
Number of bricks $N=\frac{9.8 \times 1 \times 60 \times 60}{2.5 \times 9.8 \times 3.6}=400$