In an experiment to measure his power,a student records the time taken by him in running up a flight of steps on a staircase. Use the following data to calculate the power of the student :
Number of steps = 28
Height of each step = 20cm
Time taken = 5.4s
Mass of student = 55kg
Acceleration = 9.8m s-²
due to gravity.

Dear Student,
Please find below the solution to the asked query:

Total height of reached by the student = 28 ×​ 20 / 100 = 5.6 m
work done by the student = potential energy that gets stored i him = m×g×h = 55 ×​ 9.8 ×​ 5.6
now, 
power = work done / time taken 
power = 55 ×​ 9.8 ×​ 5.6 / 5.4 = 558.96 W


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  • 6
height is 28*20steps=560cm=5.6m. power=work/time. work=mgh. 55*9.8*5.6=3018.4 joule and now power =3084.4/5.4=558.96watt
  • 1
power = work done / time taken
we know that, work done = force * displacement
and force = mass * acceleration
therefore,
power = mass * acceleration * displacement / time taken
given,
      mass (m) = 55kg
​      acceleration (a) = 9.8 ms-2
     time taken (t) = 5.4 s
     displacement (s) = 28 steps of 20 cm
                                28 * 20 = 560 cm = 5.6 m
             power = 55 * 9.8 * 5.6 / 5.4 
                         = 3018.4/ 5.4
                        = 558.962963...
                        = 558.96 watt     (approx)
 
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