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28 gru 2020 · The definition of work in physics is force times displacement. It is a scalar produced by two vectors. The angle between the force and the displacement is also factored in. Work has units of energy called joules in SI units. The work-energy theorem relates kinetic energy to net work in a system.
In physics, “work” is a measure of the energy transferred to or from an object using a force acting on the object as it moves through a distance. It’s important to understand that work is only done when a force causes displacement or movement in the direction of the force applied.
Net Work and the Work-Energy Theorem. We know from the study of Newton’s laws in Dynamics: Force and Newton's Laws of Motion that net force causes acceleration. We will see in this section that work done by the net force gives a system energy of motion, and in the process we will also find an expression for the energy of motion.
The net work \(W_{net}\) is the work done by the net force acting on an object. Work done on an object transfers energy to the object. The translational kinetic energy of an object of mass \(m\) moving at speed \(v\) is \(KE = \frac{1}{2}mv^2\).
To understand energy and conservation of energy, we must first define some terms: work, kinetic energy (KE), and potential energy (PE). We’ll get to PE in the next Chapter. Let’s look at work and KE. Definition of work done by a force: consider an object moving while a constant force F is applied to the object.
In physics, the term work has a very specific definition. Work is application of force, f f , to move an object over a distance, d , in the direction that the force is applied. Work, W , is described by the equation
We did positive work on the weight since we exerted our force in the same direction as the displacement of the weight, i.e., upward. The work done by gravity on the weight while it was lifted was negative since the force of gravity is directed in the opposite direction to the displacement.
