# Potential energy and power relationship

### Work, Energy & Power - Maths A-Level Revision

There are two forms of mechanical energy - potential energy and kinetic energy. Potential There is a relationship between work and total mechanical energy. It is derivable from conservation of energy and the application of the relationships for work and energy, so it is not independent of the conservation laws. It is in. Work, Energy and Power A-Level maths Mechanics revision section looking at Gravitational potential energy (G.P.E.) is the energy a body has because of its.

In solving work problems, one must always be aware of this definition - theta is the angle between the force and the displacement which it causes. If the force is in the same direction as the displacement, then the angle is 0 degrees.

## Mechanics: Work, Energy and Power

If the force is in the opposite direction as the displacement, then the angle is degrees. If the force is up and the displacement is to the right, then the angle is 90 degrees.

This is summarized in the graphic below. Power Power is defined as the rate at which work is done upon an object.

### Work, Energy and Power

Like all rate quantities, power is a time-based quantity. Power is related to how fast a job is done. Two identical jobs or tasks can be done at different rates - one slowly or and one rapidly. The work is the same in each case since they are identical jobs but the power is different. The equation for power shows the importance of time: Special attention should be taken so as not to confuse the unit Watt, abbreviated W, with the quantity work, also abbreviated by the letter W.

Combining the equations for power and work can lead to a second equation for power. A few of the problems in this set of problems will utilize this derived equation for power. Mechanical, Kinetic and Potential Energies There are two forms of mechanical energy - potential energy and kinetic energy.

• Work, Power, and 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. 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. 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.

That is, the power is the work done divided by the time taken to do it.

## Potential energy

A garage hoist steadily lifts a car up 2 meters in 15 seconds. Calculate the power delivered to the car. Use kg for the mass of the car.

First we need the work done, which requires the force necessary to lift the car against gravity: It has the same units as work, the Joule J.

9. Class 11th Physics - Work Energy Power - Relation in Force & Potential Energy

There are many forms of energy: Work has been done on a spring to compress or stretch it; the spring has the ability to push or pull on another object and do work on it. The force required to stretch a spring is proportional to the distance it is stretched: Find the energy stored in a tonne of water at the top of a 20 m high hydroelectric dam.

The short way is to combine the formulas, replacing F with mg and using h height in place of d: A mass is moving and can do work when it hits another object.