In physics, power is the amount of energy transferred or converted per unit time. In the International System of Units, the unit of power is the watt, equal to one joule per second. Hence the formula is valid for any general situation. The dimension of power is power pressure cooker xl 6 quart divided by time.

As a simple example, burning one kilogram of coal releases much more energy than detonating a kilogram of TNT, but because the TNT reaction releases energy much more quickly, it delivers far more power than the coal. It is the average amount of work done or energy converted per unit of time. The average power is often simply called “power” when the context makes it clear. One metric horsepower is needed to lift 75 kilograms by 1 metre in 1 second.

Power in mechanical systems is the combination of forces and movement. In particular, power is the product of a force on an object and the object’s velocity, or the product of a torque on a shaft and the shaft’s angular velocity. Mechanical power is also described as the time derivative of work. If a mechanical system has no losses, then the input power must equal the output power.

This provides a simple formula for the mechanical advantage of the system. These relations are important because they define the maximum performance of a device in terms of velocity ratios determined by its physical dimensions. In a train of identical pulses, the instantaneous power is a periodic function of time. The ratio of the pulse duration to the period is equal to the ratio of the average power to the peak power. These ratios are called the duty cycle of the pulse train. Burning coal produces around 15-30 megajoules per kilogram, while detonating TNT produces about 4. For the TNT value, see the article TNT equivalent.