Canon shooting area in polar coordinates

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SUMMARY

The discussion focuses on calculating the surface equation of cannon shots in polar coordinates, specifically for a cannon placed on the x-y plane. The key variables include the initial speed (v0), angles (α and φ), and gravity (g) acting in the -z direction. Participants emphasize the importance of using equations of motion, particularly the relationship between horizontal distance (r) and vertical height (z) to derive the desired surface equation. The final goal is to determine the trajectory of the cannonball as a function of the angles and initial speed, resulting in a surface rather than a single impact point.

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  • Understanding of polar coordinates and their application in physics
  • Familiarity with projectile motion equations
  • Knowledge of vector representation in three-dimensional space
  • Basic concepts of gravity and its effects on motion
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Homework Statement


hi,guys.
The directions of shooting e=cos\alphacos\varphii+cos\alphasin\varphij+sin\alphak
0<\varphi<=2π;\varphi -horizontally
\alpha[0,π];\alpha is vertically
initial speed=v0

I need to calculate the surface equation of canon shots (where it hits).
In other words equations of the surface which is made from canon hits.

Homework Equations


The Attempt at a Solution



My view is that i need to gain horizontal and vertical distance (r),and then i can get the desired equation.

So horizontal distance is r=t|vxy|=tv0|ex+ey|=tv0(cos\alphacos\varphii+cos\alphasin\varphij)1/2=tv0cos(\alpha)

So now i need height or in other words the distance in vertical direction(z -direction) or all together?.. I have hard time recalling use of equations of motion.
some help,please?
 
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Is there a question in the problem statement ?
You'll find equations of motion here, or otherwise ##\vec F = m\vec a## is a good one too.

List what you need under 2 and use less shorthand than in
So horizontal distance is r=t|vxy|=tv0|e_x+e_y|=tv0(cos\alphacos\varphii+cos\alphasin\varphij)1/2=tv0cos(\alpha)
 
BvU said:
Is there a question in the problem statement ?
You'll find equations of motion here, or otherwise ##\vec F = m\vec a## is a good one too.

List what you need under 2 and use less shorthand than in

Im sorry,i edited the original post,tried to be more specific.
 
Let me try to translate: you want to calculate where a cannon ball lands that is shot from a cannon that is placed on the x-y plane in an empty flatland with no atmosphere, and gravity acceleration g in the -z direction, as a function of ##\phi, \theta## v0 and g.
That right ? Something like http://www.rabidgeek.net/physics-applets/projectile-motion/ ?

Did you find something useful among the equations of motion? Or here or here ?
 
BvU said:
Let me try to translate: you want to calculate where a cannon ball lands that is shot from a cannon that is placed on the x-y plane
Yes,and the direction of cannon is described by \vec{e}=cos\alphacos\varphii+cos\alphasin\varphij+sin\alphak

Because 0<\varphi<2pi and \alpha[0,pi].Result is not one spot where it would land,but a surface which I am looking for.

Gravity g=-g\vec{k}

BvU said:
Did you find something useful among the equations of motion? Or here or here ?

Yes,I found something useful,I think I could use dv=vvt-gt2/2
 
Yes, so dv=0 has two solutions, one trivial at shooting off and one at "landing".
Bingo.
 
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