K : kinetic energy (J)

   U_s : potential energy of a spring (J)

   U_g : gravitational potential energy of a mass (J)

   F_s : force exerted by a spring (N)

   F_g : force exerted by gravity on a mass (N)

   k : spring constant of a spring (N/m)

   x : extension or compression of a spring (m)

   v : speed of a mass (m/s)

   a : acceleration of a mass (m/s²)

   m : mass (kg)

   g : g, acceleration due to gravity of a mass (m/s²)

   h : vertical displacement of a mass (m)

Newton's 2nd Law:

   Total force = mass x acceleration

Hooke's Law:

   F_s = -kx

weight (gravitational force an a mass):

   F_g = mg

kinetic energy of a mass:

   K = ½ mv²

potential energy of a spring:

   U_s = ½ kx²

gravitational potential energy of a mass:

   U_g = mgh