# How to Calculate Power of a Turning Shaft?

• I
• Soko
In summary, the power of the turning shaft can be calculated by considering the energy and power in the rotating system. However, without information on dissipative forces, it is difficult to estimate the exact power. In certain applications, such as the use of a steam traction engine as a ploughing engine, the instantaneous power from the flywheel may be relevant. This is similar to comparing the weight of a hammer to the damage it can do. The power available from the flywheel is only temporary and must be replenished after use.
Soko
Hello, can someone tell me how, or provide me a formula, to calculate the power of the turning shaft? in Nm or Watts, I don't mind. The mass (23Kgr) is turning at stable speed of 100 rpm by external independent force. The shaft is supposed to be on bearings both sides..
I made a picture to save words..

Thank you

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Soko said:
The mass (23Kgr) is turning at stable speed of 100 rpm
So the power is 0. Or in other words there is no change in KE or PE so no work is being done.

The one exception would be any losses due to friction or other dissipative forces. But there is no way to estimate those with the given information.

CWatters and russ_watters
Although the Energy in the rotating system is the most obvious measure, Power can also be relevant.
Many years ago, I was at a steam traction engine rally and there was a demonstration of a traction engine used as a 'ploughing engine', using a cable around a wheel, slung under the body of the engine. The engines operated in pairs and used the cable to pull a plough back and forth across a field. There could be large instantaneous loads when the plough came across a boulder. The horsepower rating would be a humble 35hp, which would not deal with this load. But the flywheel could overcome the problem over a short time.
The 'Instantaneous Power' available from the flywheel was, apparently, part of the spec of these engines. Sloppy terminology? Not really because it was relevant to the particular application. It's similar to comparing the weight of a hammer with the damage it can do.

Just in case you think Sophiecentaur's contradicts Dale's post that's not the case. The flywheels Sophiecentaur mentions slow down while delivering the power boost needed to get the plough past the boulder. Once past the boulder the steam engines have to bring the flywheel back up to full speed ready for the next one.

CWatters said:
Just in case you think Sophiecentaur's contradicts Dale's post that's not the case. The flywheels Sophiecentaur mentions slow down while delivering the power boost needed to get the plough past the boulder. Once past the boulder the steam engines have to bring the flywheel back up to full speed ready for the next one.
Yes. The Power that is quoted is available for a short time from Energy stored in the flywheel. When the man on the tannoy used the phrase "Instantaneous power" I did a double take but, of course the same approach is used with the spec of a motor cruiser's Radar system. 4kW pulses and the boat uses 24W of electrical power from the boat's system.

## What is the equation for calculating mass energy?

The famous equation, E=mc^2, is used to calculate the mass energy of an object. E represents energy, m represents mass, and c represents the speed of light.

## Why is it important to calculate mass energy?

Calculating mass energy allows scientists to better understand the relationship between mass and energy, and how they are interchangeable. It also helps in understanding the fundamental principles of the universe and can be applied in various fields such as nuclear physics and astrophysics.

## What is the significance of the speed of light in the mass energy calculation?

The speed of light, represented by c, is a crucial factor in the mass energy calculation because it is a constant that relates the two entities. It shows that even small amounts of mass can have a significant amount of energy due to the immense speed of light.

## Can mass be converted entirely into energy?

Yes, according to Einstein's theory of relativity, mass and energy are two forms of the same entity. In certain physical processes, mass can be completely converted into energy, and vice versa.

## How is mass energy related to nuclear reactions?

Nuclear reactions involve the conversion of a tiny amount of mass into a large amount of energy. The process is governed by the law of conservation of mass-energy, which states that energy cannot be created or destroyed, only transformed from one form to another.

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