Work on an Incline Lab

(name and period)

Purpose:

• To determine the effect of the angle of incline compared the force and work needed to pull an object up to the same height.

Hypothesis:

• What do you think will happen to the amount of work and force it takes to move a cart up the incline as the angle increases to the same height?

(Write the question and answer it)

Materials:

• Ramp and Books

• Cart

• Bar Masses (4)

• Force Scale

• Protractor

• Meter stick

Procedures:1. Place 4 masses on the cart.2. Elevate the ramp at one end by resting it on

several books to form an inclined plane at angle of 5.00°.

3. Place the cart upon the inclined plane. 4. Use a force scale to pull the cart at a constant

speed from the bottom along the inclined plane to the height of 10.0 cm.

5. Measure and record the force and the displacement along the ramp.

6. Repeat the process every 10.0° until the incline is at 75.0°.

Data:

• Mass of cart =

• Height raised =

Data Table: Force on an Incline

Angle (°) Force (N)

Distance (cm)

Work (J)

Percent Error (%)

5.00      

15.0       

25.0     

35.0       

45.0     

55.0     

65.0     

75.0     

Data:

• Mass of cart = 1.25 kg

• Height raised = 10.0 cm

Data Table: Force on an Incline

Angle (°) Force (N)

Distance (cm)

Work (J)

Percent Error (%)

5.00 1.25 114.7    

15.0  3.25 38.6     

25.0  5.25  23.7     

35.0  7.00  17.4     

45.0  8.50  14.1     

55.0  9.75  12.2     

65.0  10.75  11.0     

75.0  11.25 10.3     

Calculations: (T-Charts)Convert units if necessary!

• Calculate the work done for each of the heights (8 Total)

• Calculate the gravitational potential energy of the cart at the top of the ramp (only 1)

• Calculate the percent error of each of the inclines (8 Total) [ W – PE ]

% error = —————x100 PE

Graphs:

Include titles and units

• Graph: Angle (x-axis) and Force (y-axis)

• Graph: Angle (x-axis) and Work (y-axis)

* Draw a best fit “curve” for each graph *

Conclusion: (in paragraph form)

• Identify all of the independent, dependent and controlled variables

• Explain what each of the graphs mean• Compare your hypothesis to the data

and calculations by using your data and graph

• Explain why you think the work changed (or not) as the inclined increased

Rubric

• Title and Purpose - (2)• Hypothesis - (5)• Materials and Data - (3)• Calculations - (15)• Graphs – (15)• Conclusion - (15)• Order – (5)• Total = 60 points

Using you data to support your conclusion

2nd Law Example From Fall

NOT Using Data to Support the Conclusion

• “My data supports my hypothesis, therefore it is correct”

Using Data to Support the Conclusion

• Graph Example:• “From the Acceleration vs.

Mass graph when the mass was 0.25 kg the acceleration was 0.68 m/s/s. When the mass was increased to 1.25 kg the rate of acceleration was 0.16 m/s/s. From this data it shows that as you an increase in mass, while keeping force constant, the acceleration will decrease.”

Acceleration vs. Mass

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 0.2 0.4 0.6 0.8 1 1.2 1.4

Mass (kg)

Acce

lera

tion

(m/s

/s)

Using Data to Support the Conclusion

• Calculations Example: (Part 2)

• “When a force of 0.1 N was applied to a 0.750 kg car there was an acceleration of 0.120 m/s/s. When a 0.5 N was applied to the same car there was an acceleration of 0.462 m/s/s. From this 0.462 > 0.120 showing that if you increase force than the acceleration will also increase.”