Physics I week 8
Lab Report Name: ____________________
Section: ___________________
EXPERIMENT: Simple Machine – Lever
Experiment 1:
DATA TABLE 1: Fulcrum at _______ cm
Trial |
Load (Mass) |
Distance of Load from fulcrum |
Effort (Mass) |
Distance of Effort from fulcrum |
Ratio: Effort Distance/ Load Distance |
1 |
1 quarter |
|
1 quarter |
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2 |
2 quarters |
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1 quarter |
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3 |
3 quarters |
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1 quarter |
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4 |
4 quarters |
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1 quarter |
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Experiment 2: Part 1 – First-class lever:
DATA TABLE 2: First-class Lever, Fulcrum at _____ m
Trial |
Load (Mass, g) |
Load (Mass, N) |
Load distance, m |
Mass of 500-g Spring scale |
Spring scale reading, N |
Effort Force, N |
Effort Distance, m |
M.A. |
1 |
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62g = 0.61N |
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2 |
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62g = 0.61N |
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3 |
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62g = 0.61N |
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Example Data Table
Trial |
Load (Mass, g) |
Load (Mass, N) |
Load distance, m |
Mass of 500-g Spring scale |
Spring scale reading, N |
Effort Force, N |
Effort Distance, m |
M.A. |
1 |
100 |
1 |
0.3 |
62g = 0.61N |
10g =0.1N |
0.71N |
.45 |
1.41 |
2 |
153 |
1.5 |
0.3 |
62g = 0.61N |
45g =0.44N |
1.05N |
.45 |
1.42 |
Checking results: Workin = Workout or 1N*0.3m = 0.71N*.45m
* MA = 1/0.71 = 1.41
Experiment 2: Part 2 – Second-class lever:
DATA TABLE 3: Second-class Lever, Fulcrum at _____ m
Trial |
Load (Mass, N) |
Load distance, m |
Effort Force, N |
Effort Distance, m |
M.A. |
Example |
1.47 |
0.2 |
80g = 0.78N |
.90 |
1.9 |
1 |
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2 |
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3 |
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4 |
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etc |
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Experiment 2: Part 3 – Third-class lever:
DATA TABLE 4 (Third-class Lever), Fulcrum at _____ m
Trial |
Load (Mass, N) |
Load distance, M |
Effort Force, N |
Effort Distance, m |
M.A. |
Efficiency |
1 |
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2 |
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3 |
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Average |
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Calculations:
1. In Experiment 1 calculate the ratios of the measured distances; i.e. the rations of Effort Distance/Load Distance
2. In Experiment 2, Parts 2, 3 and 4 convert grams as needed to Newtons.
3. In Parts 2, 3, and 4 calculate M.A. for each trial of each lever type.
Questions:
- In Experiment 1 you calculated the ratios of the measured distances, i.e. the ratios of Effort Distance/Load Distance. What is the significance of these ratios? How did your calculations compare to your expectations?
- The spring balance is reasonably accurate for determining the load mass. However, the spring balance weighs 62 grams. Explain how to use the Workin = Workout principle to verify the mass of the spring balance.
- After examining the 1st class lever data what kind of general statement can be made with regards to mechanical advantage and the relationship of load distance to effort distance?
- What happens to the mechanical advantage for 2nd class levers as the load moves further away from the fulcrum?
- What is the significance of the mechanical advantage of class 3 levers?
- What class lever is represented by a fishing pole? Why?
- What kind of lever is represented by an oar used in rowing? Why?