Physics Help Forum Is terminal velocity the highest velocity for a falling object?

 Kinematics and Dynamics Kinematics and Dynamics Physics Help Forum

 Jul 14th 2014, 08:02 PM #1 Junior Member   Join Date: Jun 2014 Posts: 22 Is terminal velocity the highest velocity for a falling object? I know that air resistance increases as the speed of the object increases. With that in mind, I feel that, for an object dropped from a high location on Earth, there will be a point in time in which there is a higher magnitude of velocity before terminal velocity. -Jonathan
Jul 14th 2014, 08:36 PM   #2
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Location: Morristown, NJ USA
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 Originally Posted by jlyu002 I feel that, for an object dropped from a high location on Earth, there will be a point in time in which there is a higher magnitude of velocity before terminal velocity. -Jonathan
Why do you feel that? You're saying that "terminal" velocity isn't really "terminal" - why not?

 Jul 15th 2014, 01:18 AM #3 Junior Member   Join Date: Jun 2014 Posts: 22 Ooh I think I see it now. As the object falls, it will accelerate to zero as it encounters it's full wind resistance. Therefore, there is still acceleration, and still an increase in velocity, but a slower increase in velocity. So I guess it is acceleration that is highest during the initial fall than at terminal velocity. Please let me know if I have the correct understanding. Thanks ChipB!
 Jul 15th 2014, 04:47 AM #4 Physics Team     Join Date: Jun 2010 Location: Morristown, NJ USA Posts: 2,344 As the falling object picks up speed the wind resistance opposing it increases as the square of the velocity. So there is some speed at which the force of wind resistance is equal to the force of the object's weight. Since these two forces act in opposite directions for a falling object, from sum of F=ma you have sum of F=0, and hence a = 0. So there can be no further increase in vlocity - that's the speed known as terminal velocity.
 Jul 15th 2014, 04:48 AM #5 Senior Member     Join Date: Apr 2008 Location: Bedford, England Posts: 668 The Drag acting to slow an object down increases in proportion to the Square of the Velocity. The force acting to speed the object up (gravity) is not affected by velocity, it stays (essentially) the same. This means that as the velocity increases the difference between the drag and the force due to gravity get smaller, until at the terminal velocity they are the same. Once this balance is reached, the velocity remains constant. There are, however, some issues to consider for "non-standard" conditions like extreame altitude. At high altitude the air density is lower, which makes the drag lower, but the force to to gravity is (almost) the same. This means the terminal velocity is higher at higher altitude than at lower altitude.
 Jul 15th 2014, 10:28 AM #6 Junior Member   Join Date: Jun 2014 Posts: 22 Sweet this helped a lot!

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