true or false :
__ friction reduces the efficiency of a machine?
___an ax is an example of a wheel and axle.
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what happens to energy when work is done?
how are work, time, and power related?
name 6 types of simple machines and give examples of each.
2007-05-19 06:33:36 · 5 answers · asked by taylorakatata2007 1 in Science & Mathematics ➔ Physics
Friction takes away energy from the machine, so, yes, friction most definitely reduces efficiency.
2007-05-19 06:37:21 · answer #1 · answered by bruinfan 7 · 0⤊ 0⤋
Well, you dont ask for "much" do you? LOL!
Ok, friction "does" reduce the efficiency of a machine because it creates heat, and the machine has to "get rid" of it, and it slows down a machine.
The only "good thing" that is associated with friction is on a 'brake pad'! Then you want all the friction you can get as it will "stop" you.
Where you get an "ax" as an example of a "wheel and axle" is beyond me. An Ax is a wedge, that is simply driven into lumber to devide it.
Energy, when the work is done, is stopped. If there is no "work" being performed, there is no energy output. Energy is the result of some "force" being applied in a direction for locomotion or performance.
Given enough "power", work can be done more efficiently so that time is saved. The more power you have for a "saw" to work, the higher the performance and the greater efficency that it will "work" so that time and energy is kept to a maximum performance and shortened.
The six types of machines....
(1) Screw - Helical screw for lifting water
(2) Wedge - Devides wood when driven into it.
(3) Incline plane - makes rolling something easier than lifting it.
(4) Pulley - Able to lift great weights, wtih the more pulleys you have.
(5) Lever - Archemedies said "Give me a large enough lever, and a place to stand, and I can move the World".
(6) Fulcrum - Place for the lever to rest, so that it can move that world.
I wish you well...
Jesse
2007-05-19 06:48:21 · answer #2 · answered by x 7 · 0⤊ 0⤋
true or false :
__ friction reduces the efficiency of a machine?
True. Friction reduces the amount of kinetic energy built up by using it for heat.
___an ax is an example of a wheel and axle.
false.
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what happens to energy when work is done?
The energy is used up to do the required job. If there is not enough, the job will not be done till more energy is produced.
how are work(w), time(t), and power(p) related?
p - w
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t
the power minus the work over time...
name 6 types of simple machines and give examples of each.
inclined plane (ramp), the wedge (Door stop), the screw (a screw) , the lever ( a jack handle), the pulley (off of a flag pole), and the wheel and axle (a wheel attached in the middle to a straight cyndrical pole. to another wheel most of the time).
2007-05-19 06:57:13 · answer #3 · answered by NappingNinja 2 · 0⤊ 0⤋
IF you were lifting a weight with a rope over a pulley, would you want that pulley to run smoothly? Or have a lot of friction?
So, friction does make machines less efficient.
Does an ax have something that spins around on it? Not last time I looked. False.
When work is done energy is converted. Lifting a weight converts chemical energy into potential energy. Throwing a ball up converts chemical energy into kinetic energy which then gets converted into potential energy.
work = power * time or power = work / time
To do a certain amount of work, you can use a little power over a long time, or a lot of power over a short time.
The simple machines are:
Wheel& axle (cart)
Inclined plane (handicapped ramp)
Screw (Nut and bolt)
Wedge (ax)
lever (shovel handle)
pulley (block and tackle)
2007-05-19 06:58:23 · answer #4 · answered by Simon T 6 · 0⤊ 0⤋
false
2007-05-19 06:39:39 · answer #5 · answered by Anonymous · 0⤊ 1⤋