Thread: advanced projectile motion problem

Hello all,

I usually consider myself to be quite good at most things math related, but compared to some of the people here, I'm sure I'm very terrible at it.


I have a very advanced projectile motion problem that I need to solve (not for school). I'm trying to contact everyone I know who might have an idea how to solve this problem.

The problem is to find the angles of fire so that a moving soldier can hit a moving target with a bullet. A full specification of the problem is in the pdf I link to below. If you can't find the exact solution, an approximate answer might also be adequate.


http://www.vincentrubinetti.com/adva...ile_motion.pdf



Let me know if you are able to solve it, or even if you have any idea of how to approach solving it.


Thank you

Originally Posted by evesira

Hello all,

I usually consider myself to be quite good at most things math related, but compared to some of the people here, I'm sure I'm very terrible at it.


I have a very advanced projectile motion problem that I need to solve (not for school). I'm trying to contact everyone I know who might have an idea how to solve this problem.

The problem is to find the angles of fire so that a moving soldier can hit a moving target with a bullet. A full specification of the problem is in the pdf I link to below. If you can't find the exact solution, an approximate answer might also be adequate.


http://www.vincentrubinetti.com/adva...ile_motion.pdf



Let me know if you are able to solve it, or even if you have any idea of how to approach solving it.


Thank you

In a word (well 4 words actually): Free Fall Reference Frame

CB

Keep in mind the horizontal velocities of the bullet and the target are constant. So take their initial distance apart d=|Rx-Ry|, and the relative velocity between them v=|Sx-Vx|. This gives you an easy roundabout method to find t=d/v, the amount of time the bullet is in the air before it hits the target (if it hits the target). Use V to find (x,y) of the target after time t, and voila, you can use the equation for shooting a static target.

Unless I am mistaken, the soldier's motion is irrelevant, because the bullet and the target move independently of him/her once the gun is fired.

Originally Posted by Media_Man

Keep in mind the horizontal velocities of the bullet and the target are constant. So take their initial distance apart d=|Rx-Ry|, and the relative velocity between them v=|Sx-Vx|. This gives you an easy roundabout method to find t=d/v, the amount of time the bullet is in the air before it hits the target (if it hits the target). Use V to find (x,y) of the target after time t, and voila, you can use the equation for shooting a static target.

Unless I am mistaken, the soldier's motion is irrelevant, because the bullet and the target move independently of him/her once the gun is fired.

Given your first sentence we may assume you mean d to be the horizontal distance apart, that is not what your notation says (to be honest I don't understand your notation at that point). It looks looks v is the absolute value of the horizontal component of the shooter and targets relative velocity; In which case d/v is not the time that the projectile is in flight.


CB