Question

a boy weighing 35 kg carries a bag of 15kg climbs stairs in 5s if there are 12 steps n stairs each of 15 cm calculate power of the boy [take g as 10m/s square]

Answer 1

Your Answer is in Attachment ✌️☺️

Answer 2

Given:

Weight of a boy= $35kg$, Weight of bag= $15kg$, Time to climb the stair=$5s$, Total steps= $12\texttrm{steps}$ , Distance between each step= $15 cm$.

To find:

Power consume of the boy=?

Solution:

• Gravitational force acting on the boy$= \textrm{Mass}\times\textrm{g}=$ $35\times10=350N$
• Total gravitational force $= \textrm{Total Mass}\times \textrm{g}=$ $(35+15)\times10=50\times10=500N$
• Distance or height = $12 \textrm{steps}$ × $15 \textrm{cm}$$=180 \textrm{cm}=1.8 \textrm{m}$

• ∴ Work done by him $= \textrm{Force}\times \textrm{distance}$

        ∴ Total work done $= 500 N\times1.8m=900 J$

• Power $= \frac{Work done}{time}$

        $\frac{900}{5}=180W$

Hence, power of the boy is $180 W$