# A question about Recoil force!

1. Jun 22, 2010

### Ashkan

when it is said that the recoil of a 120mm mortar is 40 tons, which one is meant to be the recoil: the reaction force exerted from gases on the recoil mass, OR the transmitted force from recoil system to the platform or vehicle (if it is mounted on a vehicle)?

Thanks...

2. Jun 22, 2010

### Dickfore

Both, depending on context. Also, a ton is not an SI unit of force.

3. Jun 23, 2010

### tkshoe

two words: conversion factors. :P

4. Jun 23, 2010

### Dickfore

two and a half words: variation of g.

5. Jun 23, 2010

### tkshoe

one word: negligible :)

6. Jun 23, 2010

### Dickfore

How about on an inclined plane at $\alpha = 60^{\circ}$?

7. Jun 23, 2010

### tkshoe

Ok... I thought you were referring to g as gravity, and therefore variation in g would be negligible since this is not a super duper mortar. But now that you have mentioned an angle... I have no idea what you are talking about. Mind clarifying what you were referring to as "g"?

Regardless, a ton is 2000 lbs and lbs easily convert to newtons which I assume are your desired "SI" units. Hence my, albeit somewhat snide, comment about conversion factors.

8. Jun 23, 2010

### Dickfore

What is a pound a unit of?

9. Jun 24, 2010

### Ranger Mike

recoil is 80,000 pounds force exerted on the mortar's base plate...

10. Jun 24, 2010

### tkshoe

pound is a unit of force as are tons as are newtons with newtons being the SI unit of force. I am done now, this is going nowhere.

11. Jun 24, 2010

### Dickfore

Why is the amount of groceries measured in units of force?

12. Jun 24, 2010

### emiltr

1000Kg = 1 tonne. Is a unit of mass, not force. (1pound=0.45kg)

http://en.wikipedia.org/wiki/Kilogram" [Broken]

For force: 1Kgf = 1g N = 9.81 N (10N). g = gravitational acceleration (constant)

http://en.wikipedia.org/wiki/Newton_(unit)" [Broken]

From momentum conservation law.
m1V1=m2V2
m1,V1-projectile mass and speed; m2,V2- mortar mass and speed
And can calculate the force that generated the movement.
40tf (40.000 Kgf) = 400KN (400,000 N)

Last edited by a moderator: May 4, 2017