In terms of Newtons third law action and reaction.
2006-09-19 18:04:40 · 19 answers · asked by RICK B 1 in Science & Mathematics ➔ Physics
action and reaction is the answer to your question.....it usually takes two firemen to hold the hose and keep it directed on the fire...there is a lot of pressure at the exit point..............
2006-09-19 18:07:39 · answer #1 · answered by Anonymous · 0⤊ 0⤋
As another person said, you have already stated the reason.
Water gushing out at HIGH SPEEDS is the reason there is a reaction at the hose. The system of firefighter/hose nozzle is analogous to a rocket and nozzle, as the water is to hot propellant. The water, with its substantial mass and high speed creates a physical impulse which must be balanced by the same force at the hose nozzle to maintain static equilibrium.
The pressure of the water is an indirect cause. The pressure causes the water to speed up, or accelerate, through the nozzle. Anything that causes a massive substance to speed away from its projector, as a bullet from a gun, causes this same recoil effect.
2006-09-19 18:14:55 · answer #2 · answered by Anonymous · 0⤊ 0⤋
According to Newton's third law "Every action has its reaction with the same magnitude but in the opposite direction". The water moves out of the nozzle with a force. This force has a reaction on the opposite direction, which is also a force in the opposite direction. So the firemen have difficulty in holding on to the nozzle of a fire hose.
2006-09-19 18:12:15 · answer #3 · answered by ulka_bhatti 1 · 0⤊ 0⤋
There are several good answers here already. However, there is one other way to think of things involving 'exhaust'. There is pressure in the hose that is being balanced in every direction but one. The water that is in the hose is pushing in all directions at the same time. That is one of the qualities of a liquid under pressure.
Now, there are sides to the hose that push back against the water. They seem to be in balance. There is water pressure being applied at the back of the hose from what ever the water supply is (usually 20 psi or so). But, at the front of the hose there is a big hole. Nothing is pushing against the water to keep it in the hose. This means that there is water in the hose pushing in all directions on the hose except out the front. This creates the unbalanced force.
For a 1 inch nozzle on the hose with 20 psi, you would get over 60 pounds of back pressure from the hose.
2006-09-19 18:25:58 · answer #4 · answered by tbolling2 4 · 0⤊ 0⤋
You answered your own question. The water is shooting out of the nozzle in one direction, causing the hose (and the firemen) to move in the other direction from the force of the water moving.
2006-09-19 18:07:33 · answer #5 · answered by Anonymous · 1⤊ 0⤋
there is not any action and reaction involved. none what so ever. the whole phenomenon is explained by the law of conservation of momentum.
it is exactly why aeroplanes accelerate, helicopters fly etc.
in the system WATER-HOSE, when all the molecules of the water are thrusted in one direction, in order to conserve the momentum the hose must move at the opposite direction. unfotrunately the firemen cannot holp it completely parallele and the nozzles in front of the hose (to control and increase sprink effect) "guide " the water in different directions. the effect and result to it is the hos to move constantly in the opposite sirection of the water ...
2006-09-19 18:40:11 · answer #6 · answered by Emmanuel P 3 · 0⤊ 0⤋
Well, the water is basically providing thrust, like those toy rockets you used to be able to buy and hook up to your garden hose. They used water pressure to thrust the rocket up sometimes 50 feet. The fire hose is reacting to the action of the water shooting through it and, (tying it in with the first law) the firemen must act upon it with a greater force to overcome it.
Basically, they wrestle it to the ground.
2006-09-19 18:11:35 · answer #7 · answered by Space Case 2 · 1⤊ 0⤋
Why is there a question about this in the first place? Use your brains. Every forces have an equal reaction force, if the water jet shoots forward, then from the nozzle onwards, everything will be throw in the opposite direction.
2006-09-19 18:15:22 · answer #8 · answered by bluey 2 · 0⤊ 1⤋
I was a fireman EMT for 3 yrs, that hose is spitting water out at 70 gallons or more per minute, thats alot of pressure.
do you ever rinse dishes with the sprayer nozzle on the sink, multiply that times 1000, just imagine, it would shoot right out of your hand.
2006-09-19 18:11:22 · answer #9 · answered by unclesyco 3 · 0⤊ 0⤋
Well one good reason for it is the pressure of the water coming out from the nozzle. Why dont you try it then you would know.
2006-09-19 18:12:33 · answer #10 · answered by mac.dsl 2 · 0⤊ 0⤋