Finding The Tension

Finding the Tension 11/13/09

Ahmed Ali Aidrous Ali Casiano Perez Mohamed Mohamed

Purpose:

The objective of the lab is to find the tension in the string that is attached to a toy plane accelerating in a circle. The purpose is to construct a procedure to find all the variables and an equation to use those variables to find the tension.

Equipment: •

Meter stick

•

Timer

•

Plane attached to the ceiling by a string, that is accelerating in circles

•

Safety Goggles

•

Scale

Procedure:

(1)We will draw a FBD, then sum the forces, then use the sum of the forces to create an equation to find the tension. We want to then find all the variables needed to find tension, according to the equation we created. (2)We measured the string to find its length(s). (3)We used the scale to find the mass(m), to find the radius (4)we measured the distance from the plane at the highest point of its horizontal, circular flight path to the ceiling using a meter stick, then we took the plane and pulled it along the string against a meter stick touching the ceiling then pulled the plane until there was no slack then held it to the part on the meter stick we got in the previous step, then we marked where the meter stick touched the ceiling, then measured from the mark to the point where the string connects to the ceiling and that length we measure is the radius(r). (5)We used the radius to find the circumference of the planes revolution. (6)To find the velocity of the plane, we timed one revolution of the plane ten times then found the average time (t) for one revolution, then divided the circumference(C) by the t; the result is the velocity (v). (7)To find angle ( ) I used (r/s). Then we punched all those variables into our equation.

Data: Trial times for the timing of the planes revolution: Trial

1

2

3

4

5

6

7

8

9

10

Mean

Time

1.25

1.13

1.25

1.25

1.22

1.15

1.18

1.19

1.21

1.22

1.2

(seconds)

• •

r=.76m, t=1.2s,

• •

s=.80m, m=.133kg,

•

,

• •

Data Analysis:

Summed Forces: ,

•

C=2 r= 2 .76= 4.77m

•

v=C/t=4.77/1.2=3.97m/s

•

(r/s)=

(.76/.80)=18.19

We put those variables into the equation

Conclusion: The Tension in the string is 2.9 N. Possible sources of error are the timing of the revolution and the measurement of the radius of its orbit, which would have created an error in theta, which would have eventually led to an error in the Tension. If I used a motion detector to find t my results might have been more accurate. If I used a motion detector to find the radius instead of using the meter stick, I would have probably yielded more accurate results. If we were to go further, we could look for the centripetal force on the plane, and find the air resistance the plane meets in one revolution.