Quantum physics (also known as quantum theory or quantum mechanics) is a branch of physics providing a description of the behaviour and interaction of matter and energy on the scale of subatomic particles, photons and certain materials at very low temperature. The quantum realm is defined as being where the "action" (or sometimes the angular momentum) of the particle is within a few orders of magnitude of a very tiny physical constant called the Plank constant.

In physics, tension is the force exerted by a rope, string, cable, or similar object on one or more objects. Anything pulled, hung, supported, or swung from a rope, string, cable, etc. is subject to the force of tension. Like all forces, tension can accelerate objects or cause them to deform. Being able to calculate tension is an important skill not just for physics students but also for engineers and architects, who, to build safe buildings, must know whether the tension on a given rope or cable can withstand the strain caused by the weight of the object before yielding and breaking.learn how to calculate tension in several physical systems.

In physics, "work" has a different definition than it does in everyday speech. Specifically, the term "work" is used when a physical force causes an object to move. In general, if a strong force causes an object to move very far, a lot of work is done, and if the force is small or the object doesn't move very far, only a little work is done. Force can be calculated with the formula Work = F × D × Cosine(θ), where F = force (in newtons), D = displacement (in meters), and θ = the angle between the force vector and the direction of motion.