What are the two varieties of friction?

Acalorimeter uses the principle that thermal energy flows from hotter material to colder material until both reach the same

Aspring is used to stop a 50-kg package which is moving down a 20º incline. the spring has a constant k = 30 kn/m and is held by cables so that it is initially compressed 50 mm. knowing that the velocity of the package is 2 m/s when it is 8 m from the spring and neglecting friction, determine the maximum additional deformation of the spring in bringing the package to rest.

Which is the most accurate name for the ionic compound cas?