Cannon recoil WITHOUT projectile?

In summary: The rocket is able to continue accelerating even when it is far from the launching pad because the force of the escaping gases is still acting on the rocket due to Newton's third law of motion. This is similar to a person on skates pushing against a wall to move forward - the force of the fan's jet is still acting on the person, propelling them forward. In summary, the pressure in a cannon firing a heavy projectile is higher, resulting in a greater recoil compared to an empty cannon. This can be explained by the conservation of momentum. Similarly, a rocket is able to continue accelerating even when it is far from the launching pad due to the force of the escaping gases acting on it. This is in accordance with Newton's
  • #1
bunchie
8
0
Hi,

I am trying to figure out why I think that if a cannon fires a heavy projectile, the cannon's recoil is greater than for a cannon that doesn't fire any projectile at all.

Is this correct? Will the cannon firing a heavy projectile have a greater recoil than the empty, firing cannon? It seems that the pressure from the gases would be the same for both cannons, so both will be pushed back the same way.

Also, when a rocket takes off, don't the exploding gases somehow "push back" against the launching pad to accelerate the rocket? Why do I think that the rocket taking off is like a person on rolling skates pushing against a wall to start moving? Say the person was holding a powerful fan. Wouldn't they go faster if they initially directed the fan's jet against a wall rather than just air?

Please help me clarify my thought process. I've searched through other threads and haven't been able to find answers.

Thanks.
 
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  • #2
Look into conservation of momentum for the reasons behind your correct assumption about the cannons recoil.

As for the rocket. How could the rocket know what happens to the escaping gases when they are away from the rocket? Why do the escaping gases continue to propel the rocket when it is far from the pad?
 
  • #3
Pressure in the cannon firing a heavy projectile is significantly higher, because the projectile restricts expansion of the gas.

Conservation of momentum is the easy way to see that the recoil must be greater, but yes, the recoil is ultimately caused by gas pressure, so you can look at it from either perspective.
 

1. What is cannon recoil without projectile?

Cannon recoil without projectile refers to the backward movement or kick of a cannon after firing, even if there is no projectile being launched. This recoil is caused by the release of gases and pressure within the cannon upon firing.

2. Why does cannon recoil occur without a projectile?

Cannon recoil occurs without a projectile because of the basic principles of physics. When a cannon is fired, the propellant gases build up pressure inside the cannon, and upon release, they exert a force in the opposite direction of the projectile's launch, causing the cannon to recoil.

3. Is cannon recoil without projectile dangerous?

Cannon recoil without projectile can be dangerous if proper precautions are not taken. The force of the recoil can cause the cannon to move or tip over, potentially causing injury to nearby individuals. It is important to always follow safety protocols and stand at a safe distance when firing a cannon.

4. How is cannon recoil without projectile calculated?

Cannon recoil without projectile can be calculated using the laws of motion and the known mass of the cannon, the amount of propellant used, and the velocity of the projectile if it were to be launched. The equation for calculating recoil force is F = m * v, where F is the force, m is the mass, and v is the velocity.

5. Can cannon recoil without projectile be reduced?

Yes, cannon recoil without projectile can be reduced by using various techniques such as adding a recoil system or shock absorbers to the cannon, modifying the design of the cannon to distribute the recoil force more evenly, or adjusting the amount of propellant used. However, it is important to note that some recoil is necessary for the proper functioning of the cannon and reducing it too much may affect its performance.

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