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Swinging Pendulum Worksheet

Purpose In a swinging pendulum , the potential energy is converted into kinetic energy and back during the course of a swing from left to right. Potential Energy is always converting back and forth to Kinetic. Potential energy can be converted to kinetic energy by allowing the object to fall (for example, a roller coaster going down a hill or a book falling off atable.) This energy transformation also holds true for a pendulum. As a pendulum swings, its potential energy converts to kinetic and back to potential. Hypothesis: In this activity, we will prove that the transformation of energy occurs by calculating the theoretical value of velocity at which a pendulum should swing and comparing it to a measured value. Mass of pendulum ___.2 kg______ Height 1from middle __.06 m_____ Height 2 from one tape__.09 m____ Difference in height ____.03 m___ (don’t forget to convert to meters) Procedure 1. Use the pendulum and string assigned by your teacher. Record the mass of the pendulum above. 2. Place two pieces of tape on the floor on opposite sides of the hanging pendulum so that they are 0.50 m (25 cm on each side) apart with the pendulum at rest in themiddle. 3. Measure and record the height of the center of your weight when it is resting at equilibrium and again when it has swung to one of the pieces of tape. Record your data under height one and height two above. 4. Find the difference of the heights by subtracting the lesser from the greater. Convert this number into meters. Record this. Calculate theoretical values 5. Using the heightdifference you found in 4 above, calculate the potential energy of the battery. Write this here for your theoretical value of potential energy. .0588J

Gilberto Leyva

Thursday, November 29, 2012 10:06:50 AM Pacific Standard Time

10:40:f3:90:06:fc

6. If we know potential energy is conserved, what should be the theoretical kinetic energy? .0588J 7. Using the height difference you found in 4above, calculate the theoretical velocity of the battery as it should be going at the bottom of the arc. Record here. See the red equation on the board. .767 m/s

Test your hypothesis. Experiment Trial #1 1 3.288 s Time for period (T)

Trial #2 2.864 s

Trial #3 3.26 s

Trial #4 3.14 s

Average T 3.138 s

8. Using the table above, have one group member swing the battery to one of thetapes. (the edge). 9. Measure the time for the pendulum to swing to the other tape and back to its original position. Record this under Trial #1. Do this three more times, then compute the average time and record. Remember: D=1m 10.Calculate the average velocity using v = d/t. (Distance is 0.5 + 0.5m or 1m) .319 m/s

11.Using your average velocity above under #10, plug this value in to Kineticenergy and find KE in joules. .0102J

Using all of your data from #1-11, record these into the table below. Experiment 1: Potential Energy (J) .0588J Kinetic Energy (J) Velocity (m/s) .0588J .767 m/s

Theoretic values

Gilberto Leyva

Thursday, November 29, 2012 10:06:50 AM Pacific Standard Time

10:40:f3:90:06:fc

.0102J Measured data from experiment

.319 m/s


Analysis: The valuesfor theoretical should be the same as those under measured. 1. Are the values the same? No

2. Compare the theoretical velocity with measured velocity. Are they the same or different? Is one greater than the other? Different, the theoretical is bigger.

3. If the velocities are different, what are the different reasons why they are different? Human error and air resistance and gravity

4. IfI didn’t know the distance or time, could I use how we solved for theoretical velocity to find velocity? Would it be good to use theoretical velocity? Why or why not? The equation for kinetic energy. No, that’s with out thinking about possible errors.

Experiment #2 Procedure Mass of pendulum _________ Height 1 from middle _______ Height 2 from one tape______ Difference in height ________...