What is the significance of the mechanical advantage of

Question

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
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

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				62g = 0.61N
2				62g = 0.61N
3				62g = 0.61N

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: Work_in = Work_out 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
2
3
4
etc

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
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 Work_in = Work_out principle to verify the mass of the spring balance.

After examining the 1^st 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 2^nd 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?