3.4 Work
Work & Energy
Work
In physics, work has a specific meaning. If work is to be done on an object, two things must happen: (1) a force must act on the object and (2) the object must move through a distance in the direction of the force.
The amount of work done is equal to the product of the force exerted and the distance over which the force acts on the object.
W = Fd
Since force is measured in newtons (N) and distance in metres (m), work can be measured in N.m. One newton⋅metre is called a joule (J) after James Joule (1818-1889).
1 J = 1 N m
We saw in the previous video that work and energy have the same units and can equal one another in many circumstances. It takes work to change the energy of an object, such as lifting a mass to give it more potential energy, or speeding a mass up, to give it more kinetic energy. So, Work = ΔEnergy.