N m is not N m
Force, work and power. We often use these words interchangeably, but their meaning is not quite the same.
Force is what causes acceleration of mass, and it's measured in Newton . For example, a force of accelerates of mass by , or alternatively of mass by and so on.
Work is measured in Joule , which is nothing else than the acceleration of mass by a certain force over a certain distance. For example, is the amount of work required to apply a force of over a distance of , or alternatively to apply a force of over a distance of .
And finally there is power, which is work per time and is measured in Watt . For example, doing of work per second requires twice as much power as doing of work only every two seconds.
- Force — Newton
- Work — Joule
- Power — Watt
Torque vs Work
Torque is the rotational force resulting from linear force acting on a lever, and is given by the amount of linear force times the length of the lever, leaving us with as the unit. One might now think that this means that torque and work are the same thing, since work is also measured in after all. However, this is not the case, and it would in fact be invalid to use instead of for torque! The reason for this confusion is that the unit of torque is actually , but since the radian part is dimensionless, it is usually omitted.
For example, the work required for a full rotation with of torque is .
The maximum amount of torque that the engine of a Kawasaki Ninja H2R can produce is at . Given that one revolution per minute is , we can infer that the power output at this point is
which is about .