Physics

Work, Energy & Power Climbing Steps

The purpose of this lab activity is to gather data necessary to calculate the amount of work done climbing stairs and the rate work is accomplished: power. Power is measured in watts or in horsepower with 746 watts being equal to one horsepower. Work can increase potential energy and potential energy frequently converts to kinetic energy. Objects possessing kinetic energy have momentum and the change in momentum is impulse.

The work that you are going to do is lift yourself up a flight of stairs. The force that you apply to lift yourself is equal to your weight and is applied in the upward direction, opposite the earth's gravitational attraction. The distance considered when calculating work is in the same direction as the force is acting, so the distance straight up is of interest.

Data:                Time __________                                Weight __________

# of steps climbed __________                 Height of one step__________

In the following calculations, show all set-ups. List equations when possible. Be attentive to significant figures and units.

1. Calculate your weight in newtons.

2. Calculate the vertical distance that you climbed.

3. Find the work that you accomplished in the vertical direction.

4. What was your average power as you climbed the steps?

5. How many horsepower (hp) did you produce?                 Photo by Wesha / Public Domain

6. Suppose the bottom of the stairs is defined as zero potential energy. Calculate the potential energy of your body at the top to the stairs. Gravitational Potential Energy

7. Suppose you were to fall straight down the vertical distance that you ascended climbing the steps, how much time would it take you to fall?

8. How fast would you be falling just before you hit the floor?

9. Calculate your kinetic energy just before contacting the floor.

10. What is the momentum of your body just before it hits the floor?

11. You land on your feet keeping your legs stiff and since the floor gives very little, it stops you in 0.030 seconds. How much force would the floor apply to your body to stop you?

12. You land on your feet and let your knees bend upon impact. Under these conditions, it requires around 0.18 seconds to bring you to a stop. How much force would the floor apply to your body now?

13. List three different energy transformations that could occur in this activity.