Why wouldn't this scenario break the law of conservation

>>8939096
You are expending energy to move yourself, the gun, and the bullet forward. The bullet is moving 5 but from the point of reference of the gun it is moving 0. It then goes to 100m/s from that point of reference but in reality its going 105.

Unless I made a mistake, yes this is how it works. Remember, if we didn't use frame of reference then the numbers would be horseshit because of how fat Earth is moving through space.

>>8939096
>also make something go from 100m/s to 105m/s
it doesn't
the bullet is already moving at 5m/s when you pull the trigger

>>8939126
>>8939125
But the energy to get to 105m/s from 5m/s is greater than the energy required to get from 0/ms to 100m/s?

Are you telling me that energy, is relative?

the kickback slows you down retard
>>8939126
idiot

>>8939149
>the kickback slows you down
firing the gun would have to physically stop you you fucking faggot

You could realise this wouldn't work by taking it to the extreme, just imagine you throwing something out of a car that goes in 30m/s, it would look like it went far to you because you are driving at such an imense speed, but in reality it would go just as fast as if you would have thrown it in similar conditions while standing still

>ignore air resistance pls.

>>8939134
Obviously Energy is relative.

>>8939164
When you throw something out the window it still has your horizontal velocity. The only thing that slows it down is air resistance you retard.

It's a hidden version of the Oberth effect. In both cases chemical energy in the bullet cartridge is converted to the KE in the bullet, the KE recoil on the person, and the KE/heat/PE in the produced gases.

The way the chemical energy is dispersed between these depends on the speed

>>8939154
it slows you down retard

>>8939096
Let's say you and the gun have a mass of 100kg, and the bullet has a mass of 0.001kg.

In the first scenario, the starting energy is 0. After the gun is fired, the bullet moves forward at 100m/s, and you move back at 0.001m/s, conserving momentum. You have 0.0001 joules of kinetic energy, and the bullet has 10, so firing the gun added a sum of 10.0001 joules to you and the bullet.

In the second scenario, everything is moving at 5m/s, so the starting energy is 2500.025 joules. After the gun is fired, the bullet moves forward at 105m/s, and you continue moving forward at only 4.999m/s, conserving momentum. You have 2499.0001 joules of kinetic energy, and the bullet has 11.025, for a sum of 2510.0251. Again, firing the gun added a sum of 10.0001 joules to you and the bullet.

To put it another way, when firing the gun while moving forward at 5m/s, the bullet gains 11 joules while you lose 0.999 joules. When firing the gun while stationary, the bullet gains 10 joules and you gain 0.0001.

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649KB, 500x375px

>>8939224
>>8939250
/Thread

>>8939096
Delta.

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80KB, 520x750px

>>8939096
>light a firework
>firework flies off
>i wonder where it got its energy from

>>8939096
>What the fuck is momentum guys?

>>8939154
>thinking that the energy used to propel a small object a certain speed is the same as the energy required to propel a larger object at the same speed
>calling someone else retarded
Wow