Base unit (measurement) aspects of the world, such as time, distance, velocity, mass, temperature, energy, and weight, and "units" are used to describe their magnitude or quantity. Many of these quantities are related to each other by various physical laws, and as a result the units of a quantities can be generally be expressed as a product of powers of other units; for example, momentum is mass multiplied by velocity, while velocity is measured in distance divided by time. These relationships are discussed in dimensional analysis. Those that can be expressed in this fashion in terms of the base units are called .
Power (physics) yields: where "A" and "B" are the beginning and end of the path along which the work was done. The power at any point along the curve "C" is the time derivative In one dimension, this can be simplified to: In rotational systems, power is the product of the torque τ and angular velocity ω, where ω measured in radians per second. The formula_13 represents scalar product. In fluid power systems such as hydraulic actuators, power is given by where "p" is pressure in pascals, or N/m and "Q" is volumetric flow rate in m/s in SI units. If a