Kirkll wrote:hey guys .... i'm no engineer, but i've always been told velosity squared times mass divided by 450240 = KE this is saying its speed times velosity squared here. something doesn't sound right with that.... what's up with that?
Kirk, this is a very good question! I don't completely understand it. I did a little online research and came up with the following explanation that I copied from (get this) a physics forum. If you go to this forum and read it, you'll quickly see just how good the question is if even these mathematicians have a hard time explaining it. I like the explanation below because it is not so mathematical.
http://www.physicsforums.com/showthread ... 484&page=2Scroll down to Matthew Keating's post...
"Wk= Work done in accelerating object
Work done = Force x distance
If body a is travelling v m/s after 1 second, it is intuitive that it would be travelling with an average speed of v/2 m/s, so in one second it will travel a distance of v/2 m.
Now if body B was accelerated under the same force, it should also be intuitive that it will be travelling at twice the velocity after 2 seconds (velocity 2v). Over the 2 seconds it will have an average velocity of v m/s, and it follows that it will travel a distance of 2v m in that time. So body B has travelled 4 times the distance of body A in order to achieve twice the velocity, with the same applied force, thus the work done on body B is 4x the work done on body A. Now the work done on each body equates to the kinetic energy gained by each. Assuming no other external forces.
So.... doubleing the velocity causes the Ke to increase by a factor of four. You could show the same sort of arguement for a body travelling at 3v, 4v etc and you will arrive at the result that KE is proprtional to the square of the velocity.
Sorry if this is too non-mathematical"