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Elden [556K]
3 years ago
5

A machine can never be 100% efficient because some work is always lost due to .

Physics
2 answers:
konstantin123 [22]3 years ago
6 0

Efficiency of machine is defined by

\eta = \frac{W_{output}}{Q_{input}}

here we know that

W_{output} = output useful work

Q_{input} = input energy

Now here if we obtain output work same as input thermal energy then it is 100% efficient

but this is only possible when we have no energy loss while it is not possible due to many reasons

one of the main cause of energy loss is friction

So when machine working there must be friction between its working parts due to which out input energy is lost in different parts and hence we can never be 100% efficient machine.

So here main reason is FRICTIONAL LOSS

klasskru [66]3 years ago
5 0
Friction
Hope it helped
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By how much does the earth-Sun distance change? 300,000 miles 500,000 miles 3,000,000 miles 3,500 miles
iogann1982 [59]

Answer:

3,000,000 miles

Explanation:

The Earth's perihelion distance is about 147,000,000 kilometers and its aphelion distance is about 152,000,000 kilometers. So, the change in distance is about 5,000,000 kilometers which translates to about 3,000,000 in Miles.

4 0
3 years ago
An atom with a positive charge is an anion.<br> a. true<br> b. fals
Aleksandr-060686 [28]
B. False.

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4 0
2 years ago
If the voltage across a circuit element of constant resistance is doubled, how is the current through the circuit element affect
Karo-lina-s [1.5K]

Answer:

The current through the circuit element will also be doubled.

Explanation:

The relationship between voltage and current of a circuit element is given by Ohm's Law. According to Ohm's Law:

Voltage = (Resistance)(Current)

If the resistance of the element is kept constant, the relation between Voltage and Current through that element becomes as follows:

Voltage = (Constant)(Current)

Voltage α Current

Thus, the voltage is directly proportional to the current for constant value of the resistance.

Therefore, when the voltage across a circuit element of constant resistance is doubled, <u>the current through the circuit element will also be doubled.</u>

5 0
2 years ago
I appreciate any help I get on this, thank you in advanced :)
Reika [66]
The picture isn’t clear so I can’t read the dimensions of the box but I can try my best to guide u through the question.

For part a u need to find the volume of the box as that will equal the volume of sand that can be filled inside.
For this u multiply the height, width and length of the box.

For part b the mass of sand alone will be
=Mass of box + sand - Mass of empty box
=216 - 40
=176 grams

For part c the density of sand can be calculated by the formula
Density= Mass/Volume
So the mass (176g) / volume from part a

For part d u need to know that something will float if it has a lower density than what it is floating in. If the final density of sand that was found in part c is less than the density of gold (19.3 g/cm^3) it will float. Otherwise it will sink.

Hope this helped!
3 0
2 years ago
Which has more volume feathers or rocks
Nataly_w [17]
Volume doesn't depend on what the substance is, only on how much of it there is.
5 0
3 years ago
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