d.) a and b only
This is because sound needs a medium to travel. It can travel in a solid (the fastest) and air for example. Sound waves cannot propagate through a vacuum and since space is a vacuum the answer is a and b only.
The answer is C hope it helped
To solve this problem it is necessary to apply the kinematic equations of linear and angular motion, as well as the given definitions of the period.
Centripetal acceleration can be found through the relationship
Where
v = Tangential Velocity
R = Radius
At the same time linear velocity can be expressed in terms of angular velocity as
Where,
R = Radius
Angular Velocity
PART A) From this point on, we can use the values used for the period given in the exercise because the angular velocity by definition is described as
T = Period
So replacing we have to
Since 
Then the radius in meters would be
Then the centripetal acceleration would be
From the result obtained, considering that it is an unimaginably low value of an order of less than 
it is possible to conclude that it supports the assertion on the inertial reference frame.
Answer:
it is zero because the electric gap is zero within the material
Explanation:
In a metal you have many free electrons, and fixed charges formed by nuclei and electrons that are not free; therefore the charge carriers are the free electrons, these have the same negative charge and due to the lectrostatic force they repel each other as far as possible without leaving the material, this implies that at two points there must be the same potential because otherwise there would be a net Caesarian force accumulating charge in a part that would be eliminated by the Coulomb force.
With this we can review the statements the strap is: it is zero because the electric gap is zero within the material
