Unit 3 Lab Report:
Work, Energy, and
Power While
Climbing Stairs
Natalia Cullen - August 14 - SPH3U - Mrs. Price
PURPOSE
The purpose of the lab was to determine the work done and power
developed from a human while climbing a flight of stairs. For this, it was
important to know the difference between work and power; which is
that work was the amount of energy needed to move an object a certain
distance, and power was the rate at which work was done. The two were
related; power equals work divided by time (Know About Work Energy
and Power by Unacademy, 2022). Furthermore, after the difference of
work and power was known, a stopwatch, a bathroom scale, and a
metre stick were used to calculate the work and power developed by a
human while climbing stairs at different speeds.
HYPOTHESIS
For this experiment, the work done by the human should have been the
same at the different speeds because the distance was the same. On the
contrary, due to the difference in the time required for the person to
climb up the stairs at different speeds, the power should have been
different.
MATERIALS & APPARATUS
Stopwatch
Bathroom scale
Metre stick
Human (object)
Stairs
Fig. 1. Fully labelled diagram of the apparatus used for the experiment.
PROCEDURE
1. The metre stick was used to measure the vertical height of a flight of
stairs. Then this value was recorded in the observations table.
2. The bathroom scale was used to find the mass of the person in kg.
After, this value was recorded in the observations table.
3. The time required for the person to climb up the stairs at regular
speed was recorded with a stopwatch, and then added to the
observations table.
4. The time required for the person to jog up the stairs was recorded
with the same stopwatch and then added to the observations table.
OBSERVATIONS
Table 1. Shows the results recorded from the metre stick, bathroom
scale, and stopwatch. These values were then used to calculate the work
done and power developed.
ANALYSIS
Work was calculated using the values recorded in Table 1. The force due to gravity
acting on the object's mass was calculated first, then this value and the height of the
stairs was used to calculate the work done by the person. This resulted in 124kJ.
Moreover, power was calculated using the value obtained for work and the average of
the time used by the person. Two situations were compared in this experiment. The
first one was the power developed by the person while moving up the stairs, and the
second one was the power developed by the person while running up the stairs.
Since power was equal to work divided by time (Power, n.d.), the calculations
concluded that the power developed while running up the stairs (44kW) was greater
than the power developed while moving up the stairs (22kW). In fact, the calculations
showed that the power developed was doubled when the person was running up the
stairs.
ANALYSIS
Fig. 2. Calculations of the force due to gravity.
ANALYSIS
Fig. 3. Calculations of the work done by the person.
ANALYSIS
Fig. 4. Calculations of the power developed while moving up the stairs.
ANALYSIS
Fig. 5. Calculations of the power developed while running up the stairs.
DISCUSSION
A student could develop the greatest amount of power climbing the stairs by reducing
the time that they required to get to the top of the stairs. Since the work done would
be a constant in the equation P = W/t, the only way to increment the power developed
was to decrease the time required for them to get to the top of the stairs.
ERRORS
Systematic errors: The use of a bathroom scale to measure the mass of the object
might have affected the results of the experiment because it was not as precise as a
high precision laboratory balance, and that might have affected the calculations of
the amount of work done.
Random errors: The time values recorded from the stopwatch could have affected the
results of the power developed. Because there is a certain delay from when the
person started the stopwatch and when the person started climbing up the stairs. As
well as when the person arrived at the top of the stairs and when the person stopped
the stopwatch.
Experimental errors: The height of the stairs measured with the metre stick could
have not been accurate, which could have affected the calculations for the work
done. Making the work obtained in the experiment more or less than the actual work
done by the person.
CONCLUSION
In conclusion, this experiment illustrated the relationship between work and power. It
showed that the work was constant if the distance and mass of the object were
remained constant. Also, the power depended on the work done and the time that was
required for the person to get to the top of the stairs. When the person was moving up
the stairs, the power was less than the power developed while the person was running
up the stairs. Consequently, the energy used by the person was less while moving up the
stairs than the energy used by the person while running up the stairs. Finally, even
though the power developed by the person changed, the work done remained the
same. To further understand the relationship between work and power, another
experiment could be done. In which the time and distance would be constant, but the
mass would vary. This would show the relation between work, power and also the
impact of the mass of the object on these measurements.
REFERENCES
Know about work energy and power by Unacademy. (2022, February 20). Unacademy.
https://unacademy.com/content/railway-exam/study-material/physics/everything-you-needto-know-about-work-energy-and-power/
Power. (n.d.). https://www.physicsclassroom.com/class/energy/Lesson-1/Power