Como resolver gráficas de velocidad y tiempo

The speed of light in a material is 0.50 c. what is the critical angle of a light ray at the interface between the material and a vacuum?

Unpolarized light of intensity so passes through two sheets of polarizing material whose transmission axes make an angle of 60∘ with each other as shown in the figure. what is the intensity of the transmitted beam, st?

The coefficient of friction is a number that represents the resistance to sliding between two in contact with one another.