RELATIONSHIP BETWEEN WORK AND POWER

Work is called the process of transferring energy to the movement of an object by applying a force. It is usually expressed as the product of displacement and force. Power is the amount of energy transmitted per unit time.

CONTENT

CONCEPT OF WORK

WORK DONE IN FORCE FIELD

INTERCHANGEBILITY OF WORK AND ENERGY

CALCULATING WORK AND POWER

 

CONCEPT OF WORK

When the force moves the object a certain distance, the work will be done on the object. You can calculate the amount of work done. It is the product of the amount of force causing movement and the distance from which the force acts:

Work=(force causing movement) x (distance)

In physics, work is defined as the force that causes movement or displacement of an object. In the case of a constant force, work is the scalar product of the force acting on the object and the displacement caused by the force. Although force and displacement are vector quantities, due to the nature of scalar products (or dot products) in vector mathematics, the work has no direction.

WORK DONE IN FORCE FIELD

The force field is a vector field that describes the non-contact forces acting on particles at different positions in space. The work depends on the displacement and the force acting on the object.

When the particle moves along a path through the force field, the work done by the force is a line integral, and this value has nothing to do with the speed/momentum of the particle traveling along the path.

For a conservative force field: it is also independent of the path itself and depends only on the starting and ending points. Therefore, the work of an object traveling in a closed path is zero, because its starting point and end point are the same. If the field is conservative, the work done can be more easily evaluated by realizing that the conservative vector field can be written as the gradient of some scalar potential function.

Then, the work done is only the difference between this potential value in the starting and ending points of the path. If these points are given by x=a and x=b, respectively

INTERCHANGEBILITY OF WORK AND ENERGY

Energy and work can be used interchangeably because they are almost the same thing. They have the same unit, i.e. joules. For example, if someone has energy, it means that he can do some work, and if someone can do some work, it means that he has some energy.

The concept of work and energy is closely related to the concept of force, because the applied force can do work on an object and cause changes in energy. There is a strong connection between work and energy.

In a sense, when there is a net force doing work on an object, the kinetic energy of the object will change equal to the amount of work done

CONCEPT OF POWER

Power is to do work. In physics, power is the amount of energy transmitted or converted per unit of time. In the international system of units, the unit of power is watts, equal to one joule per second.

Power is a scalar.

In SI base units: kg⋅m2⋅s−3

SI unit: Watt (W)

 

CALCULATING WORK AND POWER

WORK

W = F x S (Force x displacement) (J or N)

Where F = Mass x acceleration

Work done in a force field

Work = mgh (j)

average

where t is the time interval during which work (W) is accomplished.

POWER

P = work done or energy expended (watts)

Time

Another form of power is found from W = F Δ x and substitution of average velocity of the object during time t for Δ xt: average P = F Δ x/Δ t = F(average v).

 

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