Work is the amount of energy transferred into or out of a system by a force exerted on that system over a distance. The work done by a conservative force (such as gravity or an ideal spring) is path-independent and is zero if the system returns to its initial configuration, so only conservative forces have an associated potential energy. The work done by a nonconservative force (such as friction or air resistance) is path-dependent.
A 2 kg block is at rest on a frictionless floor. A constant 10 N horizontal force pushes it through a distance of 3 m in the direction of the force. (a) Find the work done on the block. (b) How much energy is transferred into the block, and what is the block's kinetic energy afterward? (c) Find the block's final speed.
Try it on paper first, then reveal each step to check your work.