Composition of Forces
Objectives: Determine the weight of an object by vector analysis.
1. Sketch the set up.
2. Tape your blank paper on the board and place it behind the 3 strings with the knot near the center.
3. Make two sharp points on the paper directly behind each string such that a straight line can be drawn later. Accuracy is everything! Unless the three lines meet in one place, repeat this step.
4. Record the force (tension) in Newtons (N) of each spring balance. Watch significant figures!
5. Determine the mass of the object on the triple beam balance.
1. Remove the data sheet and construct a vector diagram to show all three concurrent vectors acting on the knot in the center. Include the scale, arrows, angles, magnitudes, etc.
2. Construct a parallelogram of the two spring balance forces to determine the resultant and equilibrant. Label fully.
3. Verify the magnitude of the resultant using the angle of the string from the vertical (θ) and the equation Cosθ (Force) for each string (see notes from class).
3. Determine the angle of difference between the equilibrant and your data sheet. What does this angle indicate?
4. Compare the calculated Weight (the equilibrant on your paper) with the actual Weight. Compute a % error.
5. Define the terms resultant and equilibrant.
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