Watts Your Power Lab Answers
Watts your Power? How many horses are you worth?
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 …show more content…
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 stairs is exactly the same because the work only depends on the weight of the person and the vertical displacement achieved. Since the weight of a person does not change when he or she walks or runs and since the vertical displacement does not change from time to time, the work done is exactly the same. Furthermore, since time is not considered in the equation W=Fd, time is not a factor for work. Therefore, a student whose mass is 89 kg and whose weight is 873N does the same amount of work no matter the speed at which he walks or runs because the vertical displacement(1.66 m) as well as his weight remain constant.
3. Neither the larger nor the smaller students used more power to get up the flight of stairs because mass had no effect on power. The time a person took to reach the top is essential in determining power as the work divided by the time equals power. Student C (mass=74 kg, Weight=725.9 N) created .30 horsepower while Student F (mass=63 kg, Weight=618.03) created .30 horsepower. These two students created the same power output despite their very different masses and weight and thus proving that mass had no effect on the power
generated.
4. The power used in going up the stairs swiftly and going up the stairs slowly was not the same because power is very dependent on time. The longer it takes one to do a certain amount of work, the lesser the amount of power they use. Similarly, the smaller the increment of time, the larger the power used. For example, Student B (mass=75 kg, weight =735.75) uses 244.3 watts of power when walking up the stairs and uses 678.6 watts while running up the stairs. It is important to note that since it took Student B 5.0 seconds to walk up the stairs and it took him 1.8 seconds to run up the stairs. It is this difference in times that affects the power. He used less power while walking up the stairs because he took a longer time to walk but he used more power when he decreased the time required to go up the stairs with the same vertical height of 1.66 meters.
5. Based on the data we collected and analyzed, not one single student put out more power than a horse. Student B and Student F were close to putting out a horsepower. Student B put of .91 horsepower while Student F put out .92 horsepower. The students could have put out one horsepower (746 Watts) if they had run up the distance in a shorter amount of time.
6. As a result of close analysis of our data, we can conclude that every student did put out more power than a 100watt light bulb but different individuals put out a different value for power. For example, Student A put out 157.3 watts of power when she walked the stairs while Student G put out 175.65 watts of power when she walked the stairs.
7. Compared to the power produced by the students while they ran, the power that could be produced continuously for 1 hour would be far smaller because the time increment is larger. The larger the time increment, the smaller the power output.
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 …show more content…
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 stairs is exactly the same because the work only depends on the weight of the person and the vertical displacement achieved. Since the weight of a person does not change when he or she walks or runs and since the vertical displacement does not change from time to time, the work done is exactly the same. Furthermore, since time is not considered in the equation W=Fd, time is not a factor for work. Therefore, a student whose mass is 89 kg and whose weight is 873N does the same amount of work no matter the speed at which he walks or runs because the vertical displacement(1.66 m) as well as his weight remain constant.
3. Neither the larger nor the smaller students used more power to get up the flight of stairs because mass had no effect on power. The time a person took to reach the top is essential in determining power as the work divided by the time equals power. Student C (mass=74 kg, Weight=725.9 N) created .30 horsepower while Student F (mass=63 kg, Weight=618.03) created .30 horsepower. These two students created the same power output despite their very different masses and weight and thus proving that mass had no effect on the power
generated.
4. The power used in going up the stairs swiftly and going up the stairs slowly was not the same because power is very dependent on time. The longer it takes one to do a certain amount of work, the lesser the amount of power they use. Similarly, the smaller the increment of time, the larger the power used. For example, Student B (mass=75 kg, weight =735.75) uses 244.3 watts of power when walking up the stairs and uses 678.6 watts while running up the stairs. It is important to note that since it took Student B 5.0 seconds to walk up the stairs and it took him 1.8 seconds to run up the stairs. It is this difference in times that affects the power. He used less power while walking up the stairs because he took a longer time to walk but he used more power when he decreased the time required to go up the stairs with the same vertical height of 1.66 meters.
5. Based on the data we collected and analyzed, not one single student put out more power than a horse. Student B and Student F were close to putting out a horsepower. Student B put of .91 horsepower while Student F put out .92 horsepower. The students could have put out one horsepower (746 Watts) if they had run up the distance in a shorter amount of time.
6. As a result of close analysis of our data, we can conclude that every student did put out more power than a 100watt light bulb but different individuals put out a different value for power. For example, Student A put out 157.3 watts of power when she walked the stairs while Student G put out 175.65 watts of power when she walked the stairs.
7. Compared to the power produced by the students while they ran, the power that could be produced continuously for 1 hour would be far smaller because the time increment is larger. The larger the time increment, the smaller the power output.