The Elements of Physics

Historically, some scientists believed that 4 elements (water, earth, fire, and wind) made up everything, as opposed to the elements of the periodic table we now know about. This mural pays tribute to these old elements and also encompasses some equations that are integral to physics class.

The water equations have to do with waves: n=c/v: n is the index of refraction, c is the speed of light in a vacuum, and v is the speed of light in a particular substance. V=F*lambda: speed of a wave = frequency times wavelength. Angular speed omega= 2pi/period

The earth equations have to do with gravity, the force from the earth: Normal force (balances gravity, pushes up on you from the ground) = mass times g (9.81 m/s^2) when gravity and normal force are the only forces acting in the vertical direction and there is no vertical acceleration, according to newton's 2nd law. The potential energy (U) from gravity is mass times g times height. When energy is conserved, the sum of initial and final kinetic and potential energies are equal, so 1/2mv^2 (initial KE, if PE=0) = mgh (final PE, if KE=0).

The fire equations have to do with thermodynamics, heating gasses, etc: PV=nRT: ideal gas law, pressure times volume = molar mass from periodic table times the gas constant R times temperature. This equation is useful for thermodynamics and is also used in chemistry. I don't recognise the second equation; sorry. Please let me know if you do. I think the third equation is referring to the first law of thermodynamics, which states that the change in internal energy (delta U) equals Q - W, where Q is the heat added to the system and w is the work done by the system.

The air equations have to do with things falling through the air. Friction = mu (coefficient of friction) times normal force. Vt =sqrt(2Fg/cpA) is the equation for terminal velocity (the speed that a falling object eventually reaches when air resistance prevents more acceleration), where Fg is the force of gravity (mass times g= 9.81), c is the drag coefficient, p is rho is density, and A is the cross sectional area. D=1/2cpAv^2 is the drag force equation, where D is the drag force (like air resistance), c is the drag coefficient, p is rho is the density of the fluid (such as air), A is the cross-sectional area, and v is velocity.