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Inquiry: Energy Conservation

Purpose: To verify the law of conservation of energy.


Roll a ball down the incline from a height (h) and measure the time the ball passes through the photo gates, which are 10.0 cm apart. Record data in your notebook and calculate PE at the top, KE and RE at the bottom and lost energy. Use three different balls. BE SURE TO RELEASE THE BALLS FROM THE SAME HEIGHT! Complete the table with the results of your experiment and try to explain the order by which the balls lost energy.


Inquiry Questions:

  1. Assuming there was no energy lost in our experiment, derive an equation for the velocity of a sphere in terms of height [h] and gravity [g]. What does this say about how the velocity of the spheres should have turned out in this lab?

  2. A 10.0 kg thin ring rolls on a horizontal surface at the rate of 4.0 m/s. Compute its total KE in joules.

  3. A disk has a moment of inertia (I) of 48.0 kgm2. Find the work in KJ required to increase its speed from 7.0-10.0 rev/sec?

  4. A disk rolling on a horizontal surface at 20.0 m/s comes to the bottom of an inclined plane, which makes an angle of 30.0º with the horizontal. How far up along the surface of the incline will the disk roll? (neglect friction)