SearchOnMath

The wave equation, \(\frac{\partial^2u}{\partial t^2}= c^2\nabla^2 u\), relates how \(u\) varies with time and with the spatial coordinates as a wave propagates with speed \(c\).

The heat equation, \(\frac{\partial \varnothing}{\partial t} = D \nabla^2 \varnothing\), uses the Laplacian of \(\varnothing\) to express diffusion through a medium.

Newton's mutual attraction force for masses \(m_1\), \(m_2\) is \(F=G\frac{m_1 m_2}{d^2}\), where \(d\) is the distance between them and \(G\) is the gravitational constant.