Once a differential equation is integrated, it becomes an algebraic equation; so one could say that most or all of the fundamental laws of physics can also be stated in simple algebraic form. For example, consider the relationship between position, velocity and acceleration.

1. Velocity is the rate at which position changes with time, dx/dt. If we integrate, we get the familiar equation x = vt.
2. Acceleration is the rate at which velocity changes with time, dv/dt or d(dx/dt)/dt which can be stated as d²x/dt². Integrated, we get the familiar algebraic form, x = 0.5 at², or more generally
   x = x₀ + v₀t + 0.5 at².

But only relationships in which one thing changes with respect to another are stated in terms of differential equations. For example, consider the formula for the energy of a photon, e = hn. The energy e and frequency n of a photon are related by Planck's constant h and do not change.