Old 26th Nov 2012, 07:35
  #112 (permalink)  
Join Date: Jul 2009
Location: France - mostly
Age: 80
Posts: 1,689
Hi mm43,

Thank you for sharing your exciting experiment. Thomas, the heavier engine in the first test, stopped in the shorter distance?


The problem lies not in the use of the word thrust. You are wrong when you equate momentum to a force. Momentum and force are like apples and oranges. An apple can equate to another apple, it cannot equate to an orange.

Force = rate of change of momentum (post #71).

You yourself wrote in post #90: Force = Momentum/Time

If that is correct, then Force = Momentum cannot be correct.

Let's examine the ski jumper. If we ignore the aerodynamic forces acting on him, then after leaving the ramp the only force he is subjected to is gravity. Because there is no force opposing gravity, his vertical motion slows down at the rate of 19.05 kts/second. If there were no force acting on him he would continue to move at constant speed in a constant direction.

Last edited by HazelNuts39; 26th Nov 2012 at 07:52.
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