Professor Eegerson’s Tales of the Universe introduces five physics concepts commonly used in engineering

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Newton’s Second Law of Motion

Newtonian mechanics describes the motion of bodies under a system of forces. The second law states that a change in an object’s velocity is a function of the object’s mass and amount of force applied to the object. This principle governs the motion of all things, including bicycles, autos and rockets. The book also introduces Hooke’s Law, which states that a spring’s force scales linearly to how much the spring is compressed.

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Resonance

Systems, depending on their mass and stiffness, will naturally oscillate when excited at their natural frequency. In acoustic resonance, sound waves amplify when the frequency matches the systems’s own natural frequency of vibration (e.g. a guitar string). When designing mechanical systems, engineers must ensure the resonance frequencies of component parts do not match driving vibrational frequencies of motors or other oscillating parts. Otherwise the system can literally shake itself apart.

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Phase Change

As a medium changes from one phase to another, energy is either released or absorbed. Energy is absorbed when changing from liquid to gas (vaporization) and released when changing from gas to liquid (condensation). Engineers use this phenomenon to move energy from one location to another in order to provide cooling and heating. Common cooling examples are refrigeration and air conditioning. A heat pump is capable of moving energy in either direction so it can provide both heating and cooling.

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First and Second Laws of Thermodynamics

Thermodynamics considers the effects of work, heat and energy on a system. The First Law states that the total energy of a closed system remains constant (the conservation of energy). The Second Law states that heat cannot naturally flow from a colder location to a hotter location. The book also introduces how the speed that heat flows in a medium is a function of the temperature gradient in the medium.

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Electromagnetism

Electric current running in a wire produces a magnetic field capable of exerting a magnetic force. Conversely, moving a wire in a magnetic field induces an electric current in the wire. Electric motors depend on the first phenomenon and electric generators on the latter. Today’s electric cars typically utilize both phenomena.