Lunar Rover

[k0ua]

If you had a room with a vaccume and released an air filled balloon, would it propel itself?

Absolutely. But you didn't say the room had no gravitational forces. So this room would not be an analogue for deep space. The balloon would fly about the room and fall to the floor. But it would not fly like it does in an air filled room as the lifting surface of the balloon would not come into play here as it does in an air filled room.

Also if you blew up the balloon in air pressure and then put it into the vacuum chamber it may burst as the air pressure inside the balloon would inflate it further in the vacuum.

 

[Industrial Toys]

I am having a hard time comprehending this. I could see that a firearm fired in a vaccume, would eject the projectile normally. If the back of the cartridge was open, not so sure.

 

[/pine]

In this clip from 'The Martian' at about the .30 mark the protagonist punctures the glove in his space suit and uses the pressurized suit like a thruster rocket to propel himself close enough to be rescued...(FWIW the writer is very keen on keeping all the science in his stories authentic)

The Martian (215): Mark Rescue Final Scene - YouTube

 

[k0ua]

I am having a hard time comprehending this. I could see that a firearm fired in a vaccume, would eject the projectile normally. If the back of the cartridge was open, not so sure.

Well a cartridge case that was not contained would never develop any chamber pressure vacuum or no, and never propel the projectile out of the chamber, let alone down the barrel.

 

[Industrial Toys]

I can see if you eject mass, there is an opposite reaction. But thrust isn't mass. At lease not very much except in the medium comprising that thrust.

 

[k0ua]

I can see if you eject mass, there is an opposite reaction. But thrust isn't mass. At lease not very much except in the medium comprising that thrust.

I am not sure what you just said. But I do agree that thrust is NOT mass. You eject mass in one direction and you will have thrust in the opposite direction. Works just as well down here on earth with gravity and air too. Take your shotgun with an 1 1/2 ounce turkey load. fire it South, and tell me if your shoulder doesn't move North. And better yet put your shoulder firmly up against a good big tree and fire it again, and tell me if you don't have one heck of a bruised shoulder and a lot of pain.

 

[Industrial Toys]

If you fired the shotgun in a vaccume, you would still feel the kick, but I'm still thinking if you removed the shot, you might not.

 

[4570Man]

If you fired the shotgun in a vaccume, you would still feel the kick, but I'm still thinking if you removed the shot, you might not.

If you removed the shot and wad most of the powder won’t burn and the primer isn’t strong enough for you to feel anything. If you left the wad most of the powder still won’t burn.

 

[k0ua]

If you fired the shotgun in a vaccume, you would still feel the kick, but I'm still thinking if you removed the shot, you might not.

If you removed the shot and step out your back door and fire it, it will have very little recoil as the mass ejected will just be the gas and the burned and unburned propellant being ejected. You would not even feel it. The vacuum has nothing to do with it one way or another.

It is all about that Newtons 3rd law of motion. The Vacuum doesn't matter. You don't have to have air to push against. All you have to do is eject mass. and when you are totally weightless you don't need to eject much mass to set a body in motion and once in motion it will stay in motion unless another force acts upon it.

If you are inside a space craft of course and it if filled with breathable air, the air resistance will slow and eventually stop your motion. but without the air resistance, you are the energizer bunny. Except for solar wind, and other forces even in deep space.

 

[k0ua]

If you removed the shot and wad most of the powder won’t burn and the primer isn’t strong enough for you to feel anything. If you left the wad most of the powder still won’t burn.

And for darn sure it wont activate any automatic action of any kind or cock any internal hammers. and will leave a mess of unburned propellant particles to clean up.