Neglecting friction and air resistance, the first hill must be built 4 times higher than it is now.
Answer: n = c / v" "c" is the speed of light in a vacuum, "v" is the speed of light in that substance and "n" is the index of refraction. According to the formula, the index of refraction is the relation between the speed of light in a vacuum and the speed of light in a substance.
Explanation: the relation is the vacuum and the speed of light in a substance.
Answer:

Explanation:
Given:
- relativistic length of stick A,

- relativistic velocity of stick A with respect to observer,

<em>Since the object is moving with a velocity comparable to the velocity of light with respect to the observer therefore the length will appear shorter according to the theory of relativity.</em>
<u> Mathematical expression of the theory of relativity for length contraction:</u>

where:
L = relativistic length
original length at rest
Lorentz factor 



An object with greater charge will exert a greater force on an object than an object with smaller charge would. However, if you consider two charges that exert a force on each other, regardless of the magnitude of charge, both charges will exert an equal force on each other because of Newton's third law.
Answer:
light
Explanation:
Light is part of a spectrum of electromagnetic energy that includes radio waves, microwaves, infrared radiation, visible light, ultraviolet "light", x rays, and gamma rays.