& Design
Engineering Study Notes
1. Energy in Engineering
Engineered systems change energy from one type into another. For example, there are engines that
change chemical energy into mechanical energy and electric motors that change electrical energy into
mechanical energy.
Kinetic energy is connected to movement.
Potential Energy Relates to Position or Configuration.
The connection between thermal energy and microscopic motion.
Electric energy is connected to electric charges and electric fields.
Kinetic energy: KE = ½mv²
2. Work and Power
Work in mechanics happens when there is a displacement of an object due to a force acting on it. The
term power refers to the rate at which work is done.
Work: W = Fd
Power: P = W/t
3. Efficiency
There is no actual machine that turns all the energy input into output energy. Energy is wasted in the form
of friction, heat, sound, resistance, etc.
Efficiency = Useful Energy Output / Total Energy Input × 100%