# Watts

Purpose: To determine the amount of work performed and the power developed when climbing a set of stairs and to determine the relationship between power and time. Pre-Lab Questions:

1.Power is the rate at which work is done. The work divided by the time it takes for the work to be done equals power. 2.The unit for power is the Watt which is Joules/second.

3.One horsepower (hp) is 746 watts.

Procedure:

In this lab, we calculated the work performed and the power that person creates when he or she climbs and runs a set of stairs. Each step in the stair had a vertical distance (height) of 0.166 m. since there was a total of 10 steps; the total vertical distance was 1.66 meters. Since we were only concerned with work in a vertical plane or the work done against gravity, we had to find the weight of each person by multiplying their mass and the acceleration due to gravity(9.81 m/s^2) and then multiply this number by the vertical distance(1.66m). So, our equation for work in this lab becomes W= Fgdy; where W is the work, Fg is the weight, dy is the vertical distance. Since we found the work, we can divide it by the time it took for the person to reach the top of the flight of stairs to find the power, in watts. This is represented by the equation P=W/t; where P is the power in watts, W is the work in Joules and t is the time it takes for the work to be done. Furthermore, by using the conversion factor that 1hp=746 watts, we were able to calculate the horsepower generated by the person who climbed the stairs.

Conclusion Questions:

1.Students who had more mass did more work than those who didn’t have more mass. In other words, students who were larger did more work than students who were smaller. For example; the student whose mass was 89.0 kg (873N) performed 1449.3 Joules of work whereas the student whose mass was 42.5 kg (417N) did 692.1 Joules of work. 2.The work done while running and walking the...

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