Which surface has the most friction? a An ice rink b A grassy field c A paved road

The free body diagram shows a box being pulled to the left up a 25-degree incline. the magnitude of the normal force is

Identify the theory that can be used to explain each phenomenon. answers diffraction: wave theory interference: wave theory reflection: both particle and wave theories refraction: both particle and wave theories

Two rigid transformations are used to map δhjk to δlmn. the first is a translation of vertex h to vertex l. what is the second transformation? a reflection across the line containing hk a rotation about point h a reflection across the line containing hj a rotation about point k