WORK&ENERGY

Work (W)

Work is done when an object displaces in direction of force applied. If object moves in any other direction, work is not done

Joule (J)

The SI unit of work and energy, defined as the work done by a force of one newton acting through a displacement of one meter (1 J = 1 N \cdot m)

Kinetic Energy (KE)

The energy of an object due to its motion, calculated using the formula KE = \frac{1}{2} m v^2

Work-Energy Theorem

The theorem stating that the net work done on an object is equal to its change in kinetic energy (W_{net} = \Delta KE)

i.e W=\frac12mv^2-\frac12mu^2

Gravitational Potential Energy (PE_g)

The energy stored in an object due to its position in a gravitational field, typically defined as PE_g = mgh

The higher an object is lifted above surface of earth, the more GPE it posseses

Elastic Potential Energy (PE_s)

The energy stored in an object due to its configuration - stretched or bended

Law of Conservation of Energy

A principle stating that energy cannot be created or destroyed, only transformed from one form into another or transferred between objects; the total energy of an isolated system remains constant

Mechanical Energy (ME)

The energy of an object by virtue of its motion or position.

The sum of the kinetic energy and potential energy in a system: ME = KE + PE

Power (P)

The rate at which work is done or energy is transformed over time: P = \frac{W}{t} = \frac{\Delta E}{t}

Watt (W)

The SI unit of power, equivalent to one joule per second (1 W = 1 J/s)

Power in terms of Velocity

For a constant force acting on an object moving at a constant velocity, power can be calculated as P = F \cdot v

Positive vs. Negative Work

Work is positive if the force has a component in the direction of displacement (0^\circ \le \theta < 90^\circ) and negative if the force has a component opposite to the displacement (90^\circ < \theta \le 180^\circ)

Potential energy

The energy of an object due to its position or configuration