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How much work is wasted if a machine with an input of 7500Joules only works at 70 percent efficiency?
Wiki User
∙ 12y ago
Work, or energy? The input energy is only going to be 70% of the capability of the devices' energy consumption. I believe that what is really desired here, but the structure of the question does not give this quantity, is how much loss due to inefficiency, or resistance in the machine for a given amount of input energy. The basic answer is 2150 Joules. Energy is what is available to the machine, but energy is only drawn as a result of the draw on the energy source driving the machine. To illustrate, a clothes dryer is capable of drawing 5000 watts of electrical power. Does it draw all of that power in watts every time it is turned on? No, of course not. If the dryer is set for a cycle such as air fluffing, then all the dryer will draw is enough energy in watts to make the drum turn. That is not going to anywhere near the rated 5000 watts the dryer is capable of demanding from it's power source. So, the question given is misleading. You can not put 7500 Joules of energy into a device, and make it use that amount of energy. The machine will only use what it needs to do the job it is to do, plus what it needs to over come frictional losses. Work is never lost, work is a function of what the machine does, for a given load, and it's ability to do the job asked of it. Proper use of terms leads to correct answers, while not using proper terms leads to confusion.
Wiki User
∙ 12y ago
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Does an ideal machine have an effciency of 100 percent?
No, there is not such thing as an ideal machine; it's just an idea.
Explain why the amount of work that a machine does is less than the amount put into the machine?
Output work is always less than input work.
How much energy is wasted for every 1000 megajoule?
It depends on the efficiency of the appliance. If an electric motor has an efficiency of 0.7, then for every 1000 megajoules, 30 megajoules will be wasted as useless heat or sound or other useless energy form.
What energy is wasted from a washing machine?
Sound and heat
What happens to the wasted energy in a washing machine?
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Does an ideal machine have an effciency of 100 percent?
No, there is not such thing as an ideal machine; it's just an idea.
Why is the efficiency of 1.0 is not achievable?
In any machine, some energy will usually be wasted. This will reduce the efficiency below the theoretical maximum of 1.0. However, please note that, if the efficiency is above 95% (or 0.95), when rounded to the nearest tenth you will get 1.0.In any machine, some energy will usually be wasted. This will reduce the efficiency below the theoretical maximum of 1.0. However, please note that, if the efficiency is above 95% (or 0.95), when rounded to the nearest tenth you will get 1.0.In any machine, some energy will usually be wasted. This will reduce the efficiency below the theoretical maximum of 1.0. However, please note that, if the efficiency is above 95% (or 0.95), when rounded to the nearest tenth you will get 1.0.In any machine, some energy will usually be wasted. This will reduce the efficiency below the theoretical maximum of 1.0. However, please note that, if the efficiency is above 95% (or 0.95), when rounded to the nearest tenth you will get 1.0.
Explain why the amount of work that a machine does is less than the amount put into the machine?
Output work is always less than input work.
If tight scissors have an efficiency of 50 percent half of your effort is wasted due to what?
It is due to friction.
Why does a high-efficiency machine is more desirable than low-efficiency machine?
High efficiency means that a large percentage of the energy used is converted to something useful (the desired output of the machine), and a low percentage is wasted.High efficiency means that a large percentage of the energy used is converted to something useful (the desired output of the machine), and a low percentage is wasted.High efficiency means that a large percentage of the energy used is converted to something useful (the desired output of the machine), and a low percentage is wasted.High efficiency means that a large percentage of the energy used is converted to something useful (the desired output of the machine), and a low percentage is wasted.
Why machine is not 100 percent efficiency?
Some energy (or power) is usually wasted. It is often possible to take measures to reduce it, but this can't be completely eliminated.Some energy (or power) is usually wasted. It is often possible to take measures to reduce it, but this can't be completely eliminated.Some energy (or power) is usually wasted. It is often possible to take measures to reduce it, but this can't be completely eliminated.Some energy (or power) is usually wasted. It is often possible to take measures to reduce it, but this can't be completely eliminated.
What is the difference between an ideal machine and a real machine?
In ideal machine input is equal to output . The efficiency of ideal machine is 100% . In real machine input is not equal to output .The efficiency of ideal machine in not 100% . In ideal machine there is no lose of energy . In real machine there is lose of energy . In real machine there is no friction . While in real machine there is friction .
How long does energy efficient light bulbs STAY ON?
As long as they receive energy. The energy-efficiency refers to the fact that less energy is wasted as heat.As long as they receive energy. The energy-efficiency refers to the fact that less energy is wasted as heat.As long as they receive energy. The energy-efficiency refers to the fact that less energy is wasted as heat.As long as they receive energy. The energy-efficiency refers to the fact that less energy is wasted as heat.
Why is it that efficiency of a machine is less than 1?
The efficiency is always less than one because some of the energy is always useless for what you want. Most wasted energy eventually turns into heat. therefore the efficiency is like a percentage with 1 being 100% a device can't be 100% efficient as some energy is wasted. To work out the efficiency of a device you need to do the total useful energy produced divided by the total energy that is inputted into the device
Why efficiency of solar photovoltaic cell is not 100 percent?
Because semiconductors such as silicon are indirect bandgap semiconductors, so some of the light energy is wasted as lattice vibrations (phonons).
what is efficiency?
the ability to do something well without wasted time or effort.
Why is the amount of that a machine does is less than the amount put into the machine?
In such a machine, the remaining energy is wasted to friction
