And how is momentum involved?
2007-12-09 07:44:38 · 10 answers · asked by Anonymous in Science & Mathematics ➔ Physics
By Newton's Third Law, the force at which the water is forced out of the hose has to equal the force which the water pushes back. The principles also apply to momentum, the amount (mass) of water being shot out (velocity) produces a recoil on the hose. To stop the hose from moving, the firefighter has to supply his own force on the hose, and given how much water and how power it is being shot out of the hose, the firefighter must exert a large quanity of force to counter the hose's recoil.
2007-12-09 07:52:30 · answer #1 · answered by Acorns 3 · 3⤊ 0⤋
Firefighter Water Hose
2016-10-31 11:44:09 · answer #2 · answered by ? 4 · 0⤊ 0⤋
In firefighter terms it's called nozzle reaction. Most of the time this is due to the firefighter allowing the hose to bend in the middle instead of holding it straight. The straighter the hose the lesser the nozzle reaction. This is usually why there is more than one FF on a hose, to help keep it straight.
Most hand lines are flowed at 80 to 120 psi. As the water leaves the truck and travels through the hose and over couplings and through appliances, it creates turbulence. This turbulence stirs the water and as it comes out the nozzle it wants to kick back. The more pressure or momentum the water has the greater the nozzle reaction.
2007-12-11 10:14:06 · answer #3 · answered by firelt28 5 · 0⤊ 0⤋
It has to do with conservation of momentum. Since the water is flying out of the hose with some speed v (and the water has some mass m, for example), the firefighter must move back to keep the momentum of the system constant.
To clarify:
Before the water starts spraying: the firefighter and the hose system is stationary.
After: The water is moving forward, so the firefighter has to move backward (to conserve the momentum of the system).
2007-12-09 07:53:23 · answer #4 · answered by !nv!s!ble 2 · 1⤊ 0⤋
Newton's laws. For every action, there is an equal reaction in the opposite direction. So, you have several pounds of water, flying out of the hose in one direction - that means there is a fair amount of force in the opposite direction - pushing against the firefighter.
Newton's laws essentially embody momentum. The water wants to stay at rest. If we apply force to it, in order to get it to move, we necessarily invoke the reaction.
2007-12-09 07:50:27 · answer #5 · answered by Damocles 7 · 2⤊ 0⤋
A small bend in the flexible pipe causes a travelling wave to form in the water and the pipe, causing the end to move erratically. It's a process similar to formation of meanders in rivers.
Momentum of water travelling straight in a bend tries to straighten the bend -- but as the two ends of the pipe are fixed, it tries to move the ends. The one connected to the fireman is more movable than the one connected to teh fire hydrant.
2007-12-09 07:50:51 · answer #6 · answered by baystreet690 4 · 1⤊ 0⤋
Because of all the pressure! and one of Newtons rules ( for every action there is an equal and opposite reaction!)
2007-12-09 07:49:16 · answer #7 · answered by Anonymous · 1⤊ 0⤋
recoil. For every action, there is an equal and opposite reaction.
2007-12-09 07:47:34 · answer #8 · answered by John R 7 · 3⤊ 0⤋
Thx for the answers EVERYONE <3
2016-08-26 10:42:40 · answer #9 · answered by ? 4 · 0⤊ 0⤋
the pressure behind the water
2007-12-09 07:47:19 · answer #10 · answered by thelma_layton 4 · 1⤊ 0⤋