Why is their less friction on snow than a concrete path

Because the pressure of your foot on the surface of snow or ice melts a thin layer of the surface, and the friction is very low through the very thin film of water on the surface.

  the unit of the measure =

explanation:

  the property that is quantified by the energy needed per of material to raise the temperature by one.

  si unit of energy = joule (j)

  si unit of temperature = kelvin (k)

  si unit of mass of material = kilogram (kg)

the property that is quantified by the energy needed per of material to raise the temperature by one is called specific heat.

the unit of specific heat is