Work done

Work is done when a force is applied to an object to make it move.

Work done is the same as the energy transferred to the object.

Anywhere where we have a change of energy (e.g. in all the kinetic, gravitational potential, etc. energy formulas) we can replace the energy with work done!

Units

Because work done is just another way of saying energy transferred, it has the same units: joules (J).

W=Fs

W is the work done, in joules (J)
F is the force applied, in newtons (N)
s is the displacement, in metres (m)

W=Fs\cos\theta

W is the work done, in joules (J)
F is the force applied, in newtons (N)
s is the displacement, in metres (m)
\theta is the direction of the displacement

Energy transfer

Importantly, the type of energy often changes. For example, the energy may be transferred from chemical energy in fuel to kinetic energy of a moving car.

flashcards

Question	Answer
Work done	Work is done when a force is applied to an object to make it move.
Work done is equivalent to what?	Work done is the same as the energy transferred to the object.
What are the units for work done?	Work done has the same units as energy: joules (J).
What is the formula for work done when force and displacement are in the same direction?	W=Fs, where W is work done in J, F is force in N, and s is displacement in m.
What is the formula for work done when the force is applied at an angle to the displacement?	W=Fs\cos\theta, where W is work done in J, F is force in N, s is displacement in m, and \theta is the direction of the displacement.
What can you replace with work done in energy formulas?	In all kinetic, gravitational potential, etc. energy formulas, you can replace the energy with work done.
How does the type of energy change when work is done?	The type of energy often changes, for example from chemical energy in fuel to kinetic energy of a moving car.