Why can't the output work be greater than the input work?

Answer 1

When you input force to do work, the output work cannot be greater than what is

put in, because work is energy, and energy is 'conserved'. That means it can't be

created out of nothing.

If you had a box that could put out more work than you put in, you would be king

of the world. Once you get the box going, you could take off enough of the output

work to put back into the input and keep it going, and you'd have some left over

that could be used to generate electricity, run a car, lift a load, cut wood, cook a

fish, heat a room, power a boat, weave a rug, boil water, plow a field, etc. And

your box could do any of these things without a single drop of oil or lump of coal!

It's called "perpetual motion". It's fundamentally impossible, but scam artists for

hundreds of years have been able to shake millions of dollars out of investors who

could be convinced that you can get more work out of a machine than you put it.

YOU CAN'T MAKE THE WORK OUT PUT GREATER THAN THE INPUT BECAUSE FRICTIONS ALWAYS PRESENT SO YOU WILL NEVER HAVE 100% EFFECIENCY

All machines are limited by the Laws of Thermodynamics.

The Carnot cycle shows the maximum efficiency of any process for a given temperature. Efficiency, (work output:work input), is inevitably reduced by the presence of flaws in operation and or design of the machine. Natural inefficiency factors also play a great part in this reduction: friction, air drag, rusting, etc. There has yet to be a 100% efficient machine

That's easy to answer with the law of Conservation of Energy ... energy is never

created or destroyed, it just gets moved around, a lot like snow in northern Alaska.

Put some energy into a machine, and that's the only energy that's available to come out

the other end, unless somebody pours in some more energy in the middle. Energy can

never just magically appear out of nothingness somewhere inside the machine.

The output work is less because of what is lost to heat and friction within the machine.

The output work is always slightly less than the work input work. This is because some of the work done is used to overcome friction created by the use of the machine. However the work is not lost. The output work plus the work done to overcome friction = the input work. The less work the machine does to overcome friction the greater the efficiency.

Answer 2

Because all systems possess internal friction and other kind frictions which costs some energy. as resul,t you have less work input.

Answer 3

It's not always. It just depends on the design of the specific machine. For example,

in a 3rd Class lever, the input force is greater than the output force.