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← 03-19 Solving for Acceleration

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Showing Revision 1 created 07/03/2012 by Amara Bot.

  1. Now, there's a few answers you might have given to answer this question. Let's talk about them.
  2. First, you might have used this equation, this definition of acceleration,
  3. to say okay well the ball changes its velocity by 20 meters per second by going from 0 to 20,
  4. which means Δv is equal to 20 m/sec and since it takes 2 seconds to drop
  5. Δt is equal to 2 seconds.
  6. Well, this is just the equation for acceleration and so the answer is
  7. 20/2 or 10 m/sec square.
  8. That's your first answer you may have given, maybe 10 m/sec squared.
  9. That's probably the most correct, but your second answer,
  10. which I would have been very impressed with as well is how did Galileo measure speed.
  11. This was hundred of years ago. They had no good way of measuring speed.
  12. And so the very question that I gave to you was pretty flawed in that sense.
  13. The third answer you may have given is how did he measure time.
  14. Galileo did not have any stop watches or fancy chronometers in his day.
  15. Let's see what Professor Settle has to say.
  16. To realize good results from the inclined plane needed to be able to time precise interval
  17. segments of motion down the inclined plane.
  18. He did not have chronometers--he used a pot of water with a hole in the bottom which he could
  19. fill to a certain level and which he could allow water to flow through which he could
  20. open and stop, collecting the water in a container, and then weighing the water.