Human Power

Purpose: To determine the power output of a person

Equipment: two meter metersticks, stopwatch, kilogram bathroom scale

Introduction:    Power is defined to be the rate at which work is done or equivalently, the rate at which energy is converted from one form to another.  In this experiment you will do some work
by climbing from the first floor of the science building to the second floor.  By measuring the vertical height climbed and knowing your mass, the change in your gravitational 
potential energy can be found:

∆ PE = mgh

Where m is the mass, g the acceleration of gravity, and h is the vertical height gained. 
Your power output can be determined by 
                   
                        Power  = ∆ PE/∆t,     where ∆t is the time to climb the vertical height h.

We began by taking our weight on a kilogram bathroom scale.  My mass was 77.11 kg
Next the vetical distance between the ground floor and the second floor of the science building was taken.

height = 4.29 m

 

A record keeper and a timer were assigned and at the command of the timing person we ran up the stairs.  Then we did it again for a second trial.  I returned to class and calculated my personal power output in watts using the data collected from each of my climbing trips up the stairs.   Then I got the two trials and obtainthe average power.  When everybody was done we recorded all of our trials as a class and got the average power.  Then i converted my average power output in to units of horsepower.   

 

 

Questions: Is it okay to use your hands and arms on the handrailing to assist you in your climb up the stairs?  Explain why or why not.  Yes its ok because its part of your body and its the strenght of your weight thats making the climb not just your the weight of your legs. 

 

Discuss some of the problems with the accuracy of this experiment.  The measurement of the total hight could have been a little of for we had to use a ruler to do some measurements and then use trig to solve for our hights.  Then there was the person who was incharge of the timer, the reaction time when he said "go" to the actual time we toke off.  To when we ran by him and he stoped the watch.  Those are all factors that could leave room for error. 

 

Conclusion:  Personally I felt that my times and my results of power and horse power were more on the accuarate side than a lot of the class.  In my prespective the faster you ran up the stairs the more power you are using so walking up the stairs doesnt really show how much power you got.   It shows the power that you used to get there but not the max power you have.  Since a lot of the people in class were walking up the stairs I dont believe the class average was a fair average to the amount of power we hold as a classs.  Although it was fun to get a little work out in conveting energy.