The motion of a particle sliding ([i]x[/i] metres) down a slope can be modelled using either Newtonian mechanics or Joule's law of conservation of energy. This file shows how these approaches both give a similar equation of motion for the particle.

What happens when the surface is smooth (that is, there is no friction)? (Set the coefficient of sliding friction at 0.)[br]What happens when the slope angle is π/2 radians?