Answer:
A. Light can travel trough air and space.
Explanation:
A vacuum is space that has no air inside of it. Since light is able to go through 'nothing' and matter, your answer must be A.
Answer:
A. The period of an oscillation does not depend upon amplitude.
Explanation:
The period of a spring-mass system is:
T = 1/f = 2π√(m/k)
where f is the frequency, m is the mass, and k is the spring constant.
The answer isn't B. There are no frictionless systems in the real world.
The answer isn't C or D. As shown, the frequency is a function of both the mass and the spring constant.
The answer isn't E. Turning motion into heat is not an advantage for a clock.
The correct answer is A. The period of the system does not depend on the amplitude.
The correct answer is:
<span>Point charges must be in a vacuum.
In fact, the usual form for of the Coulomb's law is:
</span>

<span>where
</span>

is the permittivity of free space
<span>q1 and q2 are the two charges
q is the separation between the two charges
However, this formula is valid only if the charges are in vacuum. If they are in a material medium, the law is modified as follows:
</span>

where

is the relative permittivity, which takes into account the dielectric effects of the material.
Just because the book is moving doesn't tell you anything about the forces on it, or even whether there ARE any.
Just look at Newton's first law of motion, and this time, let's try and THINK about it too. It says something to the effect that any object continues in constant, uniform MOTION ..... UNLESS acted on by an external force.
Answer:
The formula to find the diameter states the relationship between the diameter and the radius. The diameter is made up of two segments that are each a radius. Therefore, the formula is: Diameter = 2 * the measurement of the radius. You can abbreviate this formula as d=2r.
Explanation: