Peter Mitrano 9/25/2011Pd. 4 Honors Physics

Honors Physics Tension Pre-Lab

Purpose: This lab will examine the relationship between the angle of applied force and the magnitude of the y-component of the applied force.

Hypothesis: If the hanging mass is distributed evenly upon two strings, then the tension on the strings cannot exceed the weight of the mass. Furthermore, the tension will increase exponentially as the angle increases until an asymptote occurs at 180°, when the strings

will be unable to reach 180°

Manipulated Variable: The measured variable is the force on the springs scales placed along the two strings.

Controlled Variables: The mass on the string and the length of the string where kept constant at and ≈20 cm long

Procedure:

1. Set two ring stands about 1m apart, and slide two springs scales in the center of the rod.2. Use the rod of another ring stand and two clamps to secure the bar level between the

two other stands. 3. Place two clamps on the inside of the scales, preventing them from sliding towards the

middle of the bar.4. Attach a piece of string about 0 cm long between the hanging ends of the scales and

place weight centered on the string.5. Adjust the angle of the strings and measure the force on the spring scales. Repeat these

measurements 5-10 times.Lab Setup Diagram:

Peter Mitrano 9/25/2011Pd. 4 Honors Physics

Data:

Setup Number

Angle Measurement

Tension

1 14.5 2.622 30.0 2.583 57.0 3.44 83.5 3.495 105.9 4.46 121.0 5.497 144.6 8.38 154.8 11.4

Calculations & Results:

Calculation of ŷ tension:

F ŷ = cos(Θ/2)*Fstring

F ŷ = cos(14.5/2)*2.62

F ŷ = .992*2.62

F ŷ = 2.60

Force in the positive ŷ direction equals the cosine of the angle theta divided by two, to get the angle for one string, times the force measured on the string.

Force in the positive ŷ direction equals the cosine of the angle 14.5° divided by 2 times the 2.62N ŷ

Force in the positive ŷ direction equals .992 times the 2.62N ŷ

Force in the positive ŷ direction equals 2.60Nŷ

This graph displays the relation between the angle measure (x axis) and the force tension on the string (y axis). This graph begins to show an asymptote approaching 180°, suggesting it is a parabolic function.

Calculated Y-Component5.204.985.985.215.305.415.054.97

Peter Mitrano 9/25/2011Pd. 4 Honors Physics

Conclusion:

This lab compared the angle between two sources of tension and the force of that, as well as comparing the angle to the tension in the positive ŷ direction. The resulting data shows that the while the upwards force of the strings deviates slightly, the tension on the strings increases exponentially. The Graph of angle measure versus tension shows an exponential function, which predicts and asymptote at 180°. However, the data shows there is no relationship between the angel measure and the calculated upward tension, but supports the hypothesis stating that the upward tension should equal the weight of the mass. The data showed that the total force of the string in the positive ŷ direction when doubled equals 5.26N, which is about equal to the weight of the mass, 4.9N. The major sources of error in this lab are slight deviations of the positioning of the weight as the angle was changed, and the weight of the scales and the string. The extra weight caused small increases in calculated upwards tension, and the variance in the weight altered the measured tension by unevenly distributing weight. To futher the experiment, the setup could be turned sideways to further support Newton’s law of action and reaction by measuring horizontal tension and forces in that direction.

0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0 200.00

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10R² = 0.895937949293685

Angle vs. Tension

Angle vs Tension

Exponential (Angle vs Ten-sion)

Exponential (Angle vs Ten-sion)