Power (physics) - Wikipedia
Distance, Velocity, Momentum, Force, Pressure, Work and Energy is the position at time t = 0. Energy is the quantity that can be used to perform work. Introduction to Collisions Momentum and Kinetic Energy Thus, the average power formula over a time period is: Power in Terms of Force and Velocity. math] Power is a rate of energy transfer. The confusion comes from giving its units a name. Power is measured in watts. Energy is expressed in watt-hours, mea.
Mechanical, Kinetic and Potential Energies There are two forms of mechanical energy - potential energy and kinetic energy. Potential energy is the stored energy of position. In this set of problems, we will be most concerned with the stored energy due to the vertical position of an object within Earth's gravitational field.
- Power (physics)
Kinetic energy is defined as the energy possessed by an object due to its motion. An object must be moving to possess kinetic energy. The amount of kinetic energy KE possessed by a moving object is dependent upon mass and speed. The total mechanical energy possessed by an object is the sum of its kinetic and potential energies.
Power, Energy & Gravity
Work-Energy Connection There is a relationship between work and total mechanical energy. The final amount of total mechanical energy TMEf possessed by the system is equivalent to the initial amount of energy TMEi plus the work done by these non-conservative forces Wnc.
The mechanical energy possessed by a system is the sum of the kinetic energy and the potential energy. Positive work is done on a system when the force doing the work acts in the direction of the motion of the object.
Negative work is done when the force doing the work opposes the motion of the object. When a positive value for work is substituted into the work-energy equation above, the final amount of energy will be greater than the initial amount of energy; the system is said to have gained mechanical energy.
When a negative value for work is substituted into the work-energy equation above, the final amount of energy will be less than the initial amount of energy; the system is said to have lost mechanical energy. There are occasions in which the only forces doing work are conservative forces sometimes referred to as internal forces.
Mechanics: Work, Energy and Power
Typically, such conservative forces include gravitational forces, elastic or spring forces, electrical forces and magnetic forces. When the only forces doing work are conservative forces, then the Wnc term in the equation above is zero. In such instances, the system is said to have conserved its mechanical energy. Remember that power is equal to force times velocity equation 2 aboveand energy is power multiplied by time. This means all the solutions below will work: A power of watts for one second.
A power of A power of 2. Remember this relationship between power and energy — a small amount of power expended over a long time can accomplish the same task as a large amount of power over a short time.
But in all cases, the energy required is the same. Potential and Kinetic Energy In simple mechanical systems, energy has two primary forms — potential and kinetic. Potential energy is the energy of position or state — a coiled spring, gas under pressure, a book on a high shelf.Kinetic Energy, Gravitational & Elastic Potential Energy, Work, Power, Physics - Basic Introduction
Kinetic energy is energy of motion — an arrow in flight, a weight being lifted, a satellite in orbit. Many mechanical problems turn out to be descriptions of energy conversions — potential to kinetic and back again. This opened the steam engine up to new applications. The strongest competitor to the steam engine at the time of its invention was the horse. One of the more ingenious ways the power of the horse was harnessed was the horse mill also known as the horse gin — a large spoke and axle contraption like a wagon wheel without a rim that could be rotated horizontally.
Horses were harnessed to the ends of the spokes four to six at a time, for large applications and compelled to walk in circles around the central drive shaft for hours at a time. The human powered equivalent of a horse mill is called a treadmill. Eighteenth Century treadmills weren't anything like the exercise equipment first sold in the Twentieth Century.
Horse mills and treadmills were preindustrial machines for doing work — not the abstract mathematical work of force times displacement, but genuine back breaking, hard labor. Engraving of a horse mill Engraving of a horse mill In order for Watt to charge a licensing fee for his "rotative" steam engines, he needed an economic equivalent — something he could compare them to.
Horses were the natural choice, but how much work does a horse do? Work isn't even the right concept. One horse can do so much work, but two horses will do it twice as fast.