Question

An athelete weighting 60 kg runs up a stair case havinv 10 steps each of 0.5 m in 30 s.Calculate its power
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Answer 1

Answer:

m=60kg

distance= number of steps* distance covered in one step

=10*0.5=5m

t=30 s

g=10m/s^2

work done= change in potential energy

=mass*g*height

power= work/time

power= mgh/time

(60*10*5)/ 30 sec

power=100 joules/second

Answer 2

Given:

✭ Weight of athlete = 60 kg

✭ Steps on the staircase = 10

✭ Height of staircase = 0.5 m

✭ Time taken = 30 s

To Find:

◈ Power of the athlete?

Solution:

First we have to find the potential energy of the athlete

P.E = mgh

• m is the mass
• g is the acceleration due to gravity and
• h is the height

We have to find this because the P.E is the work done

➢ Work done

➢ ∆ PE

➢ PE f - PE i

➢ PE f - 0

➢ Work = PE f

Height climbed by the athlete will be,

➝ Number of Steps × Height of each step

➝ 10 × 0.5

➝ 5 m

Substituting these in the formula of Potential energy,

➳ P.E = 60 × 9.8 × 5

➳ P.E = 2940 J

Now power is given by,

Power = Work/Time

Substitute the values,

»» Power = 2940/30

»» Power = 98 W

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