Simple machine lever lab report

Lab Report Name: ____________________

Section: ___________________

EXPERIMENT: Simple Machine - Lever

Experiment 1:

DATA TABLE 1: Fulcrum at 15.1 cm

Trial

Load (Mass)

Distance of Load

from fulcrum

Effort

(Mass)

Distance of Effort

from fulcrum

Ratio:

Effort Distance/

Load Distance

1

1 quarter

4 cm

1 quarter

4 cm

1

2

2 quarters

4 cm

1 quarter

8.5 cm

2.125

3

3 quarters

4 cm

1 quarter

12 cm

3

4

4 quarters

3.8 cm

1 quarter

14.6 cm

3.842

Experiment 2: Part 1 - First-class lever:

DATA TABLE 2: First-class Lever, Fulcrum at 0.15 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

155

1.55

0.09

44g = 0.44N

60g =0.59N

1.03N

0.14

2

172

1.72

0.09

44g = 0.44N

90g=0.88N

1.65N

0.104

3

184

1.84

0.09

44g = 0.44N

150g=1.47N

1.91N

0.072

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 0.01 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

1.55

0.07

45g = 0.44N

0.25

2

1.55

0.07

50g = 0.49N

0.22

3

1.55

0.07

70g = 0.69N

0.15

4

1.55

0.07

95g = 0.93N

0.05

etc

Experiment 2: Part 3 - Third-class lever:

DATA TABLE 4 (Third-class Lever), Fulcrum at 0.01 m

Trial

Load

(Mass, N)

Load distance,

M

Effort

Force, N

Effort

Distance, m

M.A.

Efficiency

1

1.55

0.28

140g = 1.37N

0.25

2

1.55

0.28

150g = 1.47N

0.22

3

1.55

0.28

180g = 1.76N

0.15

Average

1.55

0.28

157g = 1.54N

0.21

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:

A. 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?

B. 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.

C. 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?

D. What happens to the mechanical advantage for 2nd class levers as the load moves further away from the fulcrum?

E. What is the significance of the mechanical advantage of class 3 levers?

F. What class lever is represented by a fishing pole? Why?

G. What kind of lever is represented by an oar used in rowing? Why?