Name ______Date ______Per ______

Energy and the Roller Coaster

Purpose:

To calculate the kinetic and potential energy of a marble along a roller coaster track. To discover how mass, velocity and height affect kinetic and potential energy. To discover if energy is conserved.

Hypothesis

Write an “If….then….” statement about how you think mass, velocity and height will affect kinetic and potential energy of the marble as it moves down the track.

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Materials:

Roller Coaster kit

CPO timers

Meter stick

Triple Beam Balance

Procedure:

Part one:Position of Marble vs. Speed of Marble

  1. Attach the roller coaster to the fifth hole on the physics stand pole.
  2. When attaching the photogates to the roller coaster, be sure that the bottom of the photogate is flat against the bottom of the track. If the photogate is not attached to the track properly, the light beam will not cross the center of the marble and your calculated speed will not be correct.
  3. Connect the photogate to input A of the timer, and set the timer to interval mode.
  4. Place the photogate at the 5 cm mark.
  5. Measure the height of the photogate from the table to the center of the hole for the light beam in meters and record.
  6. Release the marble at the top of the ramp and record the time it took the marble to cross the light beam in the data table.
  7. The distance the marble travels is equal to its diameter. The diameter of the marble is 0.0019m.
  8. The velocity of the marble is its diameter divided by the time from photogate A. Use your data to calculate the velocity of the marble and record in data table 1.
  9. Repeat steps 4 – 7 moving the photogate to the corresponding cm marks on your data table.
  10. Repeat steps 4-9 with the black plastic marble.

Part two: Potential and Kinetic Energy

  1. Potential Energyis the mechanical energy of position. In other words, potential energy is how much potentialsomething has to do work.
  2. Use the triple beam balance to find the masses of the two marbles in grams. Convert the mass into kilograms and record in data table 2.
  3. Copy your data for the height from data table 1 into data table 2.
  4. The formula used to measure P.E. is: Mass x Acceleration of Gravity (9.8) x Height
  5. Calculate the Potential Energy of each marble at each position and record.

Part three: Kinetic energy

  1. Kinetic Energy is the mechanical energy of motion. In other words, kinetic energy is how much work an object iscurrently doing.
  2. The formula for determining K.E. is: ½ (m x v2)
  3. Copy your data for the velocity of the marbles from data table 1 into data table 3.
  4. Copy your data for the mass of the marbles from data table 2 into data table 3.
  5. Calculate the Kinetic Energy of each marble at each position and record.

Part four: Total energy

  1. The total energy at each position on the roller coaster is calculated by adding the potential and kinetic energies at each position.
  2. Copy the potential and kinetic energies of the marbles from data tables 2 and 3 into data table 4.
  3. Find the total energy of each marble at each position and record in data table 4.

Analysis:

  1. How does height off the ground affect the amount of potential energy the marble has?

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  1. How would the potential energy of an object be different on the moon? Explain.

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  1. How does mass affect the amount of kinetic and potential energy the marble has?

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  1. How does the velocity at which an object is traveling affect the amount of kinetic energy the marble has?

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  1. The total energy you calculated in data table 4 should have been the same for each position. Was this the case for your data? Explain why or why not.

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Conclusion

The conclusion section needs to have five sentences:

1st sentence: Repeat the objective

2nd sentence: Describe what you did specifically in the lab to achieve the objective.

3rd sentence: State your hypothesis and use your data to explain if it correct or not and why.

4th sentence: Share what you learned.

5th sentence: This is a general summary of the lab. It ties into the first sentence of the purpose.

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Data Table 1

Photogate Placement / Height
(m) / Time of Steel Marble (sec) / Time of Plastic Marble (sec) / Distance Traveled by marble (m) / Velocity of Steel Marble (m/sec) / Velocity of Plastic Marble (m/sec)
5 cm
45 cm
85 cm
125 cm

Data Table 2

Photogate Placement / Height(m) / Mass of Steel Marble (kg) / Mass of Plastic Marble (kg) / Potential Energy of Steel Marble (J) / Potential Energy of Plastic Marble (J)
5 cm
45 cm
85 cm
125 cm

Data Table 3

Photogate Placement / Mass of Steel Marble(kg) / Mass of Plastic Marble (kg) / Velocity of Steel Marble (m/sec) / Velocity of Plastic Marble (m/sec) / Kinetic Energy of Steel Marble (J) / Kinetic Energy of Plastic Marble (J)
5 cm
45 cm
85 cm
125 cm

Data Table 4

Photogate Placement / Potential Energy of Steel Marble (J) / Potential Energy of Plastic Marble (J) / Kinetic Energy of Steel Marble (J) / Kinetic Energy of Plastic Marble (J) / Total Energy of Steel Marble (J) / Total Energy of Plastic Marble (J)
5 cm
45 cm
85 cm
125 cm