Question

electromagnetic vs. mechanical
speed
electromagnetic mechanical
this graph is accurate because ...
a mechanical waves move faster than electromagnetic waves.
b electromagnetic waves cannot travel through a vacuum.
c mechanical waves cannot travel through a medium.
d electromagnetic waves move faster than mechanical waves.

Explanation:

Electromagnetic waves travel at the speed of light in a vacuum ($3\times10^{8}$ m/s), while mechanical waves' speeds vary greatly depending on the medium but are generally much slower. For example, sound (a mechanical wave) travels at about 343 m/s in air at room - temperature.

Answer:

D. electromagnetic waves move faster than mechanical waves.