Its the same. The gun is heavy so it recoils slower for the same energy (e=mv2). Its easy to get confused if you watch hollywood films as the bullet knocks someone over. Real bullets can't impart anymore force than the recoil of the gun and shooter.
Maybe that's why ambulances go so fast. If the ambulance picks you up when it's parked and speeds up to 70mph when it takes you to the ozzie it will restore the deceleration. That's why you feel so much better when to get to A 'n E.
Bill
Oops, that means what I said isn't quite correct.
I just did some sums and the energy in a 9mm bullet is about 500 joules. The gun weighs about a kilo and gets an energy of about 10 joules.
The classic socialist nonsense.
actually, it isn't.
consider a car travelling at 100mph.
It has a certain energy.
It can be stopped safely or slammed into a concrete wall. The energy (loss) is the same.
The acceleration is dramatically different.
Peak force is what smashes bones and beaks blood vesse4ls
More bollocks from the man who knows nothing.
The force is dependent on how fasts the bullet is STOPPED or STARTED. Not how fast its going.
The energies are radically different but their momentums are the same.
E = 1/2mv^2 p = mv
(with different masses)
If you want to see the unequal masses recoil in action find a pair of differently sized superballs (the things that bounce almost perfectly).
Be sure to do this outside and well away from anything breakable and wear eye protection. Place the small ball on top dead centre of the larger ball and drop the whole assembly vertically to the ground.
The small ball will suffer a very big rebound!
The thing you should remember from this is :
Avoid head on collisions (especially with 40T trucks).
The average motorists faith in non-inertial braking when sat nose to tail a car length apart in the outside lane at 80+mph is truly scary.
No. But it slowed down.
If you somehow contrive to have it hit something without decelerating, it won't cause any damage. But that's not possible.
If it hits you, it won't continue doing a constant 70mph. It will experience an equal but opposite reaction force to the force it exerts on you. But that force will decelerate it much less than it accelerates you, because its mass is much bigger than yours.
-- Richard
It's possible that a few molecules on the front of it did, resulting in them becoming closer to the rest of the train, perhaps leaving a dent.
-- Richard
Well, technically they can if the exhaust gas is used to balance the recoil. But your point is sound :)
Unless you were including the gas ;-)
I would say it's (peak-force times time).
If I slap your face, it's a high peak force for a short time. It stings but it does little damage.
How fast is the tennis ball going?
Because you apply a force to make them accelerate - so you are doing work on the object. If the object is free to move (i.e. you are not dissipating much of that work overcoming friction, then you are in effect storing that energy in the momentum of the object.
Once moving it has kinetic energy, which has to be dissipated when it hits something.
Where the Energy E = 1/2 m v^2
You could even do the sums to work out how hard it would hit you ;-)
Because some of that force put into the car that hits you is used to accelerate you! Brian
course it is. I've hit many a speed limit without decelerating.
It is not high peak force in crash terms.
bones break and blood vessels burst at 100- 200g. That's at least a solid punch in the face
When you get hit by a car, you don't travel at constant velocity. You get accelerated to the same speed as the car, then you get decelerated back down to zero when you hit the road.
Well in my experience, its actually a whole lot more complicated than that, at least in the two case where I have seen someone killed in front of my own eyes..
Yet you still have a licence?
No reason to assume he was driving. Besides which, 1 in 5 motorists convicted of causing death by dangerous or careless driving get away without a ban, and those banned are usually back on the road after a couple of years. And most deaths don't even result in any conviction.
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