Why do trains use steel wheels rather than rubber tires? a) steel wheels provide more grip, making it easier to stop a train.
b) rubber tires don't provide enough friction to allow the train to move.
c) steel wheels increase friction, thus making it easier to move the load.
d) steel wheels reduce friction, thus requiring less force to move the load.

Describe the path of the electric current through a circuit?

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?

In a simplified model of the human eye, the aqueous and vitreous humors and the lens all have a refractive index of 1.40, and all the refraction occurs at the cornea, whose vertex is 2.60 cm from the retina. what should be the radius of curvature of the cornea such that the image of an object 40.0 cm from the cornea’s vertex is focused on the retina?