Work If a constant force F acts on an object as it undergoes a displacement d, the work done by the force on the object during the displacement is W = Fdcos where W = work done in Joules (J) F = force in N d = displacement in m = angle (180 or less) between the direction of F and the direction of d Note: 1 J = 1 Nm
Requirements in order for work to be done 1. Force need to be exerted 2. There must be a displacement 3. The force must be exerted in such a way that it has a component that is in the same direction or opposite to the direction of the displacement.
Energy The capacity of a physical system to do work.
Work-Energy Calculation When a system gains or loses energy from its environment because of work done on the system by forces origination in the environment, then the change in the systems energy is W = E f – E i Rearranging and substituting for the different types of energy results to KE i + PE gi + PE si + W = KE f + PE gf + PE sf
Law of conservation of energy In a closed, isolated system, energy is not created or destroyed, but rather, is conserved. KE i + PE gi + PE si = KE f + PE gf + Pe sf