Physics Help Forum Conversion of energy problem

 Kinematics and Dynamics Kinematics and Dynamics Physics Help Forum

 Apr 20th 2011, 04:00 PM #1 Member   Join Date: Jul 2010 Posts: 70 Conversion of energy problem The solutuion to question 12 of http://www.vcaa.vic.edu.au/vce/studi...ysics22004.pdf is that potential energy is converted to kinetic energy: 1/2 * mv^2 = mgh but say there were a point Z at the 'corner' of the left curve (so on the same level as X). Surely there was some initial kinetic energy *and* potential energy that got all converted to the kinetic energy at the level where Y is. xtheunknown0
Apr 20th 2011, 04:18 PM   #2

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 Originally Posted by xtheunknown0 The solutuion to question 12 of http://www.vcaa.vic.edu.au/vce/studi...ysics22004.pdf is that potential energy is converted to kinetic energy: 1/2 * mv^2 = mgh but say there were a point Z at the 'corner' of the left curve (so on the same level as X). Surely there was some initial kinetic energy *and* potential energy that got all converted to the kinetic energy at the level where Y is. xtheunknown0
I'm not quite sure what you are saying about point Z. If the car is to get to Z, which is on the same level as X then it would have to have been pushed, ie would have to have been given some kinetic energy, as you say. But the ground at point X is (presumably) slightly sloped so the car will start to move down the slope without someone giving it kinetic energy, so we don't need the extra push.

-Dan
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 Apr 20th 2011, 06:01 PM #3 Member   Join Date: Jul 2010 Posts: 70 Once you assume that the whole thing is slightly sloped, then it makes sense. So thanks!

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