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#16
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Re: paper: Parabolic Trajectory Calculations
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#17
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Re: paper: Parabolic Trajectory Calculations
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#18
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From a known height of 3 meters the calculation follows a freefall model (Vy=0 @t=0) which uses Vy=gt and Y=0.5gt^2.
Thus t=sqrt(3m/9.8m/sec^2/0.5sec)=0.78 seconds. Vy terminal=0.78sec*9.8m/sec^2=7.66m/sec The Newtonian trajectory equations do use the initial velocity Voy as follows: Vy=Voy-gt Y=Voyt-0.5gt^2 @ Vy=0 the arc is at its peak X=Voht Voy=Vo*sin(launch angle from horizon) Vox=Vo*cos(launch angle) |
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#19
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Re: paper: Parabolic Trajectory Calculations
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#20
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The Newtonian model equations ignore drag which calculates a velocity only on the basis of gravity. My answer is only valid for a drag free Newtonian calculation. Terminal velocity with drag provide an upper velocity limit for a falling object. For a falling baseball it would be about 33m/sec (~108ft/sec) while a hail stone is ~14m/sec (45ft/sec). A 3 meter drop reaches a peak velocity of 7.66m/sec (~26ft/sec) which is less than the maximum terminal velocity. of either of the above examples.
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#21
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Re: paper: Parabolic Trajectory Calculations
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https://en.wikipedia.org/wiki/Terminal_velocity Please read it. You are using a different definition. |
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#22
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Re: paper: Parabolic Trajectory Calculations
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Perhaps what you meant is constant acceleration model equations ignore air drag. |
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#23
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Re: paper: Parabolic Trajectory Calculations
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I've recently received a couple of PMs asking about the formulas in the spreadsheet. I'm going to post summaries of the answers here so interested students may benefit: Some cells are hidden to make the user interface cleaner. To make those cells visible: Unhide columns GHIJK, move the graph out of the way, and highlight the whole spreadsheet. The air drag acceleration vector D always points 180 degrees opposite to the Velocity vector V. The magnitude of D is modeled as: (V2/Vt2)*g ... where Vt is the magnitude of the terminal velocity. The magnitude of the X component of D is (V2/Vt2)*g*cos(θ) = (V2/Vt2)*g*(Vx/V) = (V*Vx/Vt2)*g The magnitude of the Y component of D is (V*Vy/Vt2)*g Last edited by Ether : 19-01-2017 at 21:50. |
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