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Conservation of Energy

Conservation of Energy. 012-10999 r1.04. Conservation of Energy. Introduction. Each page of this lab that contains the symbol

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Conservation of Energy

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  1. Conservation of Energy 012-10999 r1.04

  2. Conservation of Energy Introduction Each page of this lab that contains the symbol should be inserted into your journal. After completing a lab page with the snapshot symbol, tap (in the upper right corner) to insert the page into your journal. Journals and Snapshots The Snapshot button is used to capture the screen. The Journal is where snapshots are stored and viewed. The Share button is used to export or print your journal to turn in your work. Note: You may want to take a snapshot of the first page of this lab as a cover page for your journal.

  3. Conservation of Energy Lab Challenge How does the energy of a cart poised at the top of a hill compare to its energy at the bottom of the hill?

  4. Conservation of Energy Background Gravitational Potential Energy, or energy of position, is defined by the equation: GPE = mgh For an object on earth, the mass m and the acceleration due to gravity g, remain constant. Hence, only the change in height h influences any change in Gravitational Potential Energy GPE.

  5. Conservation of Energy ...Background For kinetic energy, or energy of motion, the equation is: For this same object of constant mass, any change in the kinetic energy KE is due to a change in velocity v. 1 2 KE = mv2

  6. Conservation of Energy ...Background For a closed system the Total Energy TE is defined to be the sum of the different types of energy: TE = KE + GPE + Heat + Light + … We will create our own closed system, and limit the forms of energy changing to Kinetic and Gravitational Potential to observe how they change, and how they relate to the Total Energy of the system. TE = KE + GPE

  7. Conservation of Energy Materials and Equipment Collect all of these materials before beginning the lab • Motion Sensor • Cart with Plunger • Angle Indicator • Track Bumper • Rod Clamp • Dynamics Track • Rod Stand • Balance (1 per class)

  8. Conservation of Energy Sequencing Challenge The steps to the left are part of the procedure for this lab activity. They are not in the right order. Determine the correct sequence of the steps, then take a snapshot of this page. A.From your graph determine the distance d travelled by the cart. B.Connect the track to the rod stand using the rod clamp. C.Use distance d travelled and angle of track θ to find the maximum height h that the cart travelled. D.Begin collecting data, then tap the release button launch the cart.

  9. Conservation of Energy Setup • Attach the End Stop to one end of the Dynamics Track then use the rod clamp to attach the opposite end of the track to the rod stand. • Attach the Motion Sensor to the inclined end of the track with the face of the sensor pointed toward the end stop • Make certain that the switch on the top of the motion sensor is set to the cart icon: Note:It is best to have the Rod Stand positioned next to the Motion Sensor so that it does not interfere with the sensor.

  10. Conservation of Energy Setup Record the mass of your cart in the text box below then take a snapshot of this page. • Mount the angle indicator to the side of the track as close to the motion sensor as possible. • Connect the Motion Sensor to the SPARK Science Learning System. • Use a balance to measure the mass of your cart, then record that value in kg in the text box to the right. • Place the cart with the plunger extended on the track against the end stop.

  11. Conservation of Energy Setup Tap to begin data collection. After a few seconds tap to stop data collection. Record the initial position of the cart relative to the Motion Sensor from the digits display into the text box to the right, and then take a snapshot of this page.

  12. Conservation of Energy Setup Make your selection below then take a snapshot of this page. • Q1: Why is the cart set in position with the plunger extended? • To determine the length of the plunger. • To determine if the cart is existential. • To determine the point of maximum spring compression. • To determine the point where the plunger is no longer influencing the motion of the cart.

  13. Conservation of Energy Setup Once you have settled on a suitable track incline angle, record the angle θ in the box below, then take a snapshot of this page. Press the plunger on the dynamics cart all the way into the cart until it locks in place. Place the cart at the bottom of the track, resting the plunger end of the cart against the fixed end stop. Tap the plunger release trigger on the top of the cart launching the cart up the track. Observe how far up the track the cart travels. Adjust the angle θ of the track such that the cart does not get closer than 15 cm to the Motion Sensor when launched. Note:The plunger release trigger is found on the top of the plunger-end of th`ecart.

  14. Conservation of Energy Collect Data Press the plunger all the way into the cart until it locks in place. Set the cart at the bottom of the track. Tap to begin data collection. Tap the plunger release trigger launching the cart up the track. Let the cart bounce once or twice, then tap to stop data collection.

  15. Conservation of Energy Analysis • Use graph tools to find the distance d between where the cart left the bumper to the cart's closest point to the Motion Sensor. • * To Find the Difference Between Two Data Points: • Tap to open the tools palette. • Tap and then tap two points on the data run. • Adjust using both buttons and then tap . • Tap to display the differences.

  16. Conservation of Energy Analysis Once you have calculated the maximum height h and the potential energy GPEof the system, record them below, and then take a snapshot of this page. Use the distance d travelled and the angle of the track θ to calculate the maximum height h that the cart travelled. Use h, the acceleration due to gravity g(9.8 m/s2), and the mass of the cart m to calculate the GPEof the system with the cart at the top of the track. GPE = mgh

  17. Conservation of Energy Analysis • Use graph tools to determine the initial velocity v of the cart when the cart left the bumper. • * To Find the X- and Y-Values of a Data Point: • Tap to open the tools palette. • Tap and then tap a data point. • Tap or to select nearby data points.

  18. Conservation of Energy Analysis Given that the cart momentarily comes to a complete stop before rolling back down the track, what is the Kinetic Energy of the system at this point? Why? Enter your answer in the text box below, then take a snapshot of this page.

  19. Conservation of Energy Analysis Once you have calculated theKE of the system, record that value as well as your value for vin the text box below. Use the initial velocity of the cartvand the mass of the cart m to calculate the kinetic energy of the system with the cart at the bottom of the track. 1 2 KE = mv2

  20. Conservation of Energy Analysis If the point at which the cart leaves the bumper is the lowest point of the system, what is the Gravitational Potential Energy of the system at this point? Why? Enter your answer in the text box below, then take a snapshot of this page.

  21. Conservation of Energy Analysis • Use graph tools to help determine the GPE of the system at a third point in time before the first bounce. Enter the calculated GPEvalue in the text box below.

  22. Conservation of Energy Analysis • Use graph tools to help determine the KE of the system at the same point in time on the curve. Enter the calculated KE value in the text box below.

  23. Conservation of Energy Analysis Using your calculated values from the previous two pages, calculate the total energy of the system at the third point in time. How does the total energy of the system compare at the three different points in time that you investigated? Was energy conserved? Explain your answer.

  24. Conservation of Energy Analysis • At what point in the cart's path was the Kinetic Energy of the system greatest? Where did that original energy come from?

  25. Conservation of Energy Analysis In observing the motion of the cart, the second and third bounce of the cart were lower than the first, indicating less energy. Where did the energy go? In what form was it when it was lost?

  26. Conservation of Energy Synthesis • An archer's bow can store 80 J of energy when drawn. If all that energy is converted to Kinetic Energy when the arrow is released, how fast is the 0.1 kg arrow traveling when it leaves the bow?

  27. Conservation of Energy Multiple Choice Question Make your selection below then take a snapshot of this page. • How much Gravitational Potential Energy does a 4 kg jug of milk, set on the edge of a counter1.2 m above the ground have? • 47.1 J • 471 J • 0 J • There is not enough information to draw a conclusion.

  28. Conservation of Energy Multiple Choice Question Make your selection below then take a snapshot of this page. • A bobsled and rider have 100 kg of mass combined. They come off a hill at 72 kph. Assuming all of their Gravitational Potential Energy was converted to Kinetic Energy, how high was the hill? • 204 m • 42 • 20.4 m • 264.2 m

  29. Conservation of Energy Multiple Choice Question Make your selection below then take a snapshot of this page. • A giant pendulum swings up to a height of 10 meters above the floor. When it reaches the bottom of its swing it is traveling at 14 m/s. What is the mass of the pendulum? • 1000 kg • 100 kg • 9.81 kg • There is not enough information to draw a conclusion.

  30. Conservation of Energy Congratulations! You have completed the lab. Please remember to follow your teacher's instructions for cleaning-up and submitting your lab.

  31. Physics Template References ALL IMAGES WERE TAKEN FROM PASCO DOCUMENTATION, PUBLIC DOMAIN CLIP ART, OR WIKIMEDIA FOUNDATION COMMONS: http://commons.wikimedia.org/wiki/File:Rollercoaster_dragon_khan_universal_port_aventura_spain.jpg http://commons.wikimedia.org/wiki/File:Energy-p-k-i.svg http://commons.wikimedia.org/wiki/File:Acela_2000.jpg http://www.freeclipartnow.com/office/paper-shredder.jpg.html

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