1.3. Work, Energy, and Power (A3)

Work is the transfer of energy through a force causing displacement in the direction of the force.
When energy is transferred into a system, it can increase kinetic or potential energy, or overcome forces like friction.
Work done by a system can move objects, stretch springs, or lift weights—essentially, it’s how energy gets things done.

Instead of using kinematic equations, we can apply the work-energy principle
This is especially useful when forces are not constant, or when acceleration isn’t easily known.
For example, if a car gains speed, you can find its final velocity using 1/2mv^2 = Fd avoiding the need to calculate acceleration directly.

Work tells us how much energy is transferred.
Energy conservation allows us to predict outcomes
Power measures the rate of doing work, which is useful in real-world applications like engines, electrical systems, or elevators.

the principle of the conservation of energy
that work done by a force is equivalent to a transfer of energy
that energy transfers can be represented on energy bar charts and Sankey diagrams
that work W done on a body by a constant force depends on the component of the force along the line of displacement
that work done by the resultant force on a system is equal to the change in the energy of the system
that mechanical energy is the sum of kinetic energy, gravitational potential energy and elastic potential energy
that in the absence of frictional, resistive forces, the total mechanical energy of a system is conserved
that if mechanical energy is conserved, work is the amount of energy transformed between different forms of mechanical energy in a system, such as:
- the kinetic energy of translational motion
- the gravitational potential energy
- the elastic potential energy
that power developed P is the rate of work done, or the rate of energy transfer
efficiency in terms of energy transfer
energy density of the fuel sources