Week 9
Lab Report Name: ____________________
Section: ___________________
EXPERIMENT: Simple Machine – Lever
Experiment 1:
DATA TABLE 1: Fulcrum at _______ cm
Trial
Load (Mass)Distance of Load
from fulcrumEffort
(Mass)Distance of Effort
from fulcrumRatio:
Effort Distance/
Load Distance
1
1 quarter
1 quarter
2
2 quarters
1 quarter
3
3 quarters
1 quarter
4
4 quarters
1 quarter
Experiment 2: Part 1 – First-class lever:
DATA TABLE 2: First-class Lever, Fulcrum at _____ m
TrialLoad
(Mass, g)Load
(Mass, N)Load distance,
mMass of
500-g
Spring scaleSpring scale
reading, NEffort
Force, NEffort
Distance, m
M.A.
1
62g = 0.61N
2
62g = 0.61N
3
62g = 0.61N
Example Data Table
TrialLoad
(Mass, g)Load
(Mass, N)Load distance,
mMass of
500-g
Spring scaleSpring scale
reading, NEffort
Force, NEffort
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
TrialLoad
(Mass, N)Load distance,
mEffort
Force, NEffort
Distance, m
M.A.
Example
1.47
0.2
80g = 0.78N
.90
1.9
1
2
3
4
etc
Experiment 2: Part 3 – Third-class lever:
DATA TABLE 4 (Third-class Lever), Fulcrum at _____ m
TrialLoad
(Mass, N)Load distance,
MEffort
Force, NEffort
Distance, m
M.A.
Efficiency
1
2
3
Average
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?
