Answer:
Explanation:
Given
Diameter 
radius 
From diagram, at top point
If Normal force is equal to Gravitational force

where N=normal reaction
m=mass of car
Normal reaction will provide centripetal force

thus



Light will travel more slowly in a material with a higher index of refraction
Answer: (C) Slide against each other
Explanation:
Think about rubbing our palms together, and they get warm that right there is friction.