Question about waves

What is friction? how does it affect the motion of an object?

A14 kg rock starting from rest free falls through a distance of 5.0 m with no air resistance. find the momentum change of the rock caused by its fall and the resulting change in the magnitude of earths velocity. earth mass is 6.0 * 10^24 kg. show your work assuming the rock earth system is closed.

Which of the following is not a physical property of mattera. melting pointb.heat of combustionc. viscosityd. boiling point