Answer:
The best option is for the following option m = 15 [g] and V = 5 [cm³]
Explanation:
We have that the density of a body is defined as the ratio of mass to volume.

where:
Ro = density = 3 [g/cm³]
Now we must determine the densities with each of the given values.
<u>For m = 7 [g] and V = 2.3 [cm³]</u>
![Ro=7/2.3\\Ro=3.04 [g/cm^{3} ]](https://tex.z-dn.net/?f=Ro%3D7%2F2.3%5C%5CRo%3D3.04%20%5Bg%2Fcm%5E%7B3%7D%20%5D)
<u>For m = 10 [g] and V = 7 [cm³]</u>
<u />
<u />
<u>For m = 15 [g] and V = 5 [cm³]</u>
<u />
<u />
<u>For m = 21 [g] and V = 8 [cm³]</u>
<u />
<u />
Frequency= velocity of light/wave length
Fr= 3×10^8/510×10^-9
Frequwency=5.88×10^14 Hz
<span>C.
Sample C would be best, because the percentage of the energy
in an
incident wave that remains in a reflected wave from this material
is the
smallest.
The coefficient of absorption is the percentage of incident sound
that's absorbed. So the highest coefficient of absorption results in
the smallest </span><span>percentage of the energy in an
incident wave that remains.
That's what you want. </span>
Whichever has the most mass so probably or trailer SUV