Question

A boy of mass 40 kg runs up flight of 50 steps each 10 cm high in 5 second. Find

i) the work done by the boy ii) the power developed. (g = 9.8 ms-2)​

Answer 1

Answer:

Given :-

Mass of body = 40 kg

Number of steps = 50

Height of each step = 10 cm

Time = 5 second

To Find :-

Work done

Power

Solution :-

Firstly we will find work done

\fbox{W = mgh}

W = mgh

Here,

W is the Work

M is the Mass

G is the Gravity

H is the Height

Total height = Numer of step × Height of one 1 step

Total height = 50 × 10

Total height = 500 cm [Here we will write as 5 m]

\tt \: W = 40 \times 9.8 \times 5W=40×9.8×5

\tt \: W = 200 \times 9.8W=200×9.8

\tt \: W = 1960 \: JW=1960J

Hence :-

Work Done is 1960 Joule

Now,

Let's find Power

As we know that

\rm{P = \dfrac WT }P=

T

W

Here,

P is the power

W is the Work Done

T is the Time

P=

5

1960

P=392watt