Impact angle help needed.

• Mar 14th 2010, 05:54 AM
wirenut67
Impact angle help needed.
I am new to the forum, and it has been many years since I have had to deal with any problems like this one. My memory fails me on how to resolve this.

I am trying to determine the angle of impact of a projectile that has struck a vertical wall. The projectile was fired from an elevation, and I am trying to determine the angle.

The hole is oval in shape and it 8mm high by 4mm wide.

Sine (i) = minor/major
Sine (i) = 4/8
i = sin -1(4/8)
i = 30o

I believe I have this part correct, what I can not recall is the relation of this angle. Is this 30 degrees from the vertical plane, above the point of impact, or 30 degrees from below the point of impact?

Thanks for any help with this.

Mike
• Mar 14th 2010, 06:55 AM
Sudharaka
Quote:

Originally Posted by wirenut67
I am new to the forum, and it has been many years since I have had to deal with any problems like this one. My memory fails me on how to resolve this.

I am trying to determine the angle of impact of a projectile that has struck a vertical wall. The projectile was fired from an elevation, and I am trying to determine the angle.

The hole is oval in shape and it 8mm high by 4mm wide.

Sine (i) = minor/major
Sine (i) = 4/8
i = sin -1(4/8)
i = 30o

I believe I have this part correct, what I can not recall is the relation of this angle. Is this 30 degrees from the vertical plane, above the point of impact, or 30 degrees from below the point of impact?

Thanks for any help with this.

Mike

Dear Mike,

I don't quite understand what you say!! Can you please type the question as it is?? What I don't understand is what do you mean by the hole? Also what angle are you trying to determine?
• Mar 14th 2010, 07:08 AM
wirenut67
I am referring to the hole created by the projectile when it struck the wall.

I am trying to determine the point of origin of the shot.

The hole created by the bullet measures 8mm high and 4mm wide.

I am trying to determine what angle the shooter was from the horizontal plane. In other words, what angle was the shooter shooting down at?
• Mar 14th 2010, 07:36 AM
Sudharaka
Quote:

Originally Posted by wirenut67
I am new to the forum, and it has been many years since I have had to deal with any problems like this one. My memory fails me on how to resolve this.

I am trying to determine the angle of impact of a projectile that has struck a vertical wall. The projectile was fired from an elevation, and I am trying to determine the angle.

The hole is oval in shape and it 8mm high by 4mm wide.

Sine (i) = minor/major
Sine (i) = 4/8
i = sin -1(4/8)
i = 30o

I believe I have this part correct, what I can not recall is the relation of this angle. Is this 30 degrees from the vertical plane, above the point of impact, or 30 degrees from below the point of impact?

Thanks for any help with this.

Mike

Dear Mike,

I think it could be either of the two situations.(i.e 30 degrees from the vertical plane above the point of impact or 30 degrees from below the point of impact.) Please refer to the attached drawing.

• Mar 14th 2010, 08:24 AM
wirenut67
What I am saying is that the bullet hole is 4mmx8mm and I am trying to determine the angle of entry in relation to the horizontal plane.

Forgive me, I am a bit rusty at this.
• Mar 14th 2010, 04:35 PM
Sudharaka
Quote:

Originally Posted by wirenut67
What I am saying is that the bullet hole is 4mmx8mm and I am trying to determine the angle of entry in relation to the horizontal plane.

Forgive me, I am a bit rusty at this.

Dear wirenut67,

Of course in the diagram that I have attached I have drawn the hole 4mmx8mm. Since this is confusing can you try to draw a diagram and explain this??

The diameter of the bullet hole is constant and it is perpendicular to the circumference of the hole. That is why I had marked the diameter of the hole as 4mm. So the hole is oval shaped when it is viewed from outside, but if you consider a perpendicular cross section, it is circular.