Gravity holds the system together
The answer to this is A. this is because, refraction with a light or sound wave changing its direction involve propagation,(in which propagation is the change in direction of a light or sound wave)
P=M(mass)G(Gravity)H(Height)
Gravity=9.8
M=1.5 G=9.8 H=35
so multiply all
=514.5 potential energy
The speed of a mechanical wave depends on the mechanical properties
of the medium through which the wave is traveling.
The speed of an electromagnetic wave depends on the electrical properties
of the medium through which the wave is traveling.
It's pretty well unanimous for choice <em>A</em> .
