The refractive index for glycerine is

, while for air it is

.
When the light travels from a medium with greater refractive index to a medium with lower refractive index, there is a critical angle over which there is no refraction, but all the light is reflected. This critical angle is given by:

where n1 and n2 are the refractive indices of the two mediums. If we susbtitute the refractive index of glycerine and air in the formula, we find the critical angle for this case:
Velocity because it gives the displacement and time
Answer:
Compaction and cementation
Explanation:
Cementation: As ions are deposited by fluids to form a compound that hardens loose sedimentary rocks.
Compaction: As the density of sedimentary rocks on edge of them are forced together through sediments.
If the net force is 4 N, and Frankie is pulling the rope with 7 N, Carol must be pulling the rope with 11 N (I think that Carol is going to win the tug-of-war...).
Static friction is what you are looking for.
Kinetic friction is the force exerted on an already moving object, slowing it down.