Question

State work energy theorem.

Answer 1

The Work-Energy Theorem

The principle of work and kinetic energy (also known as the work-energy theorem) states that the work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle. This definition can be extended to rigid bodies by defining the work of the torque and rotational kinetic energy.

The work W done by the net force on a particle equals the change in the particle’s kinetic energy KE:

$\text{W}=\Delta \text{KE}=\frac{1}{2}{\text{mv}}_{\text{f}}^2-\frac{1}{2}{\text{mv}}_{\text{i}}^2$

where $v_i$ and $v_f$ are the speeds of the particle before and after the application of force, and m is the particle’s mass.