Equipment:

String, spring scales, 1.00 kg hooked mass, supports, meter stick, protractor, 20-N spring scales.

Objective:

During this lab, you will investigate the relationship between the angle of an applied force and the magnitude of one component. You will compare your actual force with the theoretical force and provide a computer generated data table that calculates the theoretical values. You will graph your actual and theoretical values and provide a complete table of % errors for your results. Your paragraph will discuss all the questions below in depth.

Procedure and Data:

1. Tie the two pieces of string to the scales.

2. Hang a 1.00kg mass from the center of the string and move the clamps together such that the total angle between the two strings is about 15 degrees (half angle = 7.50).

3. Use the protractor to measure the exact angle between the strings. Record the angle and the force (scale reading) in the table. Also measure the appropriate sides of the triangles and compute the angles trigonometrically.

4. Move the strings farther apart and repeat Step 3. Continue this procedure until you have at least eight readings and are almost at the limit of your spring scales. Be sure to have some readings at angles greater than 1350. Be sure the scales have equal readings for each data point.

Hanging weight = _________ kg x 9.8 m/s2 = _________ N protractor

trigonometry

Force (N)

Theoretical Force Protractor (N)

Theoretical Force Trigonometry (N)

1. Graph the measured force and theoretical force versus the angle for angles determined both ways. Calculate percent errors for each method and discuss your results.

2. How does changing the angle affect the force on each string?

3. For what angle of the string were the forces on the strings the least, the greatest, the closest to equaling the suspended weight? Draw a free body diagram to illustrate each case.

4. Explain how the arithmetic sum of the two measured forces can be greater than the load.

5. Give some practical applications of this study.

September 25, 2013