Physics 4A Lab 3: FORCE TABLE AND VECTOR ANALYSIS
Parts List
Part
Force Table
and
Accessories
Quantity
1
50 Gr.
Hanger
4
Assorted
masses
1 set
TOTAL OF
1770 gr.
Physics 4A Lab 3: FORCE TABLE AND VECTOR ANALYSIS
Print Names:
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Part I. Simulations online:
IA Addition of vectors using tip to tail technique.
If A = 6i+4j, B = -5i+8j and C = 4i –6j compute the following operations and record their values in the table:
A+B
B–A
A+B–C
B–A+C
Go to: http://www.engapplets.vt.edu/statics/resultant/ifmres2.html and check your answers.
IB Addition of 2 vectors using component method.
Go to: http://www.phy.ntnu.edu.tw/java/vector/vector.html
R = A + B : Vectors A and B are given in polar coordinates (r, ).Units are meters and degree. Complete the table for each trial.
Express your resultant angle as a positive number.
Vector A
(130,28)
Ax
Ay
Vector B
(110,135)
(95,320)
(100,25)
(85,120)
(100,140)
(120,25)
(120,115)
(130,12)
(125,210)
Bx
By
Rx
Ry
R (r, )
Part II Balancing 3 Forces
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Using the graphical parallelogram method you will find the resultant vector R = A + B where
A=(600 grams, 300) , B= (400 grams, 1300 )
Determine a scale for drawing the vectors on the sheet so they are as large as possible but R will fit on the sheet.
Scale: 1 mm = _______gram
Using a ruler and a protractor, accurately draw R = A + B and then measure the magnitude and angle of vector –R.
Use the component method to calculate the balancing force and compare your results with the graphical method. Your graphical
method and component method should agree within a percent or two. If they don’t, redo the graphical method more carefully.
Include your calculation in your lab. Make it neat and pretty! (You can do it on the graph page!)
Scaled Values for A and B (mm) A: __________________ B: __________________
Predicted Values from graph: -R: (R, ) (mm, ): _______________ , (g, ): _______________
Predicted Values from Component Method:
-R: (g, ): _______________
Percent Difference Between Methods: (g, ):__________________________
Part III Balancing 4 Forces
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Now Repeat the above process for predicting the balancing fourth force with the graphical method when three forces are given:
A=(250 grams, 300) , B= (475 grams, 1100 ) and C=(325 grams, 3000 ).
Use the component method to derive the balancing force and compare your results with the graphical method. Your graphical
method and component method should agree within a percent or two. If they don’t, redo the graphical method more carefully.
Include your calculation in your lab. Make it neat and pretty! (You can do it on the graph page!)
Scale: 1 mm = _______gram
Scaled Values (mm) A: __________________ B: __________________ C: __________________
Predicted Values from graph: -R: (R, ) (mm, ): _______________ , (g, ): _______________
Predicted Values from Component Method:
-R: (g, ): _______________
Percent Difference Between Methods: (g, ):__________________________
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After you have finished your predictions, show your work to the instructor.
On the force table, place pulleys at the positions of vectors.
Pass the strings attached to the central ring through pulleys and hang the appropriate amount of mass from it. Don’t forget that
the hanger has a mass of 50 grams.
If your predictions are correct, all the forces should be balanced and the center pin should be located in the center of the ring.
If the forces don’t balance, try to find the location and mass of balancing force by trial and error.
If the forces balance, try perturbing the system. Does it return to equilibrium?
Explain your results in a brief summary.
Your Lab Report Must Include:
1.
2.
3.
4.
5.
Two page lab report with data.
Two vector diagrams.
Derivations of –R using the component method for Part III.
Brief summary of your results.
Don’t forget to PRINT the lab partner names on the report.