Answer:
I THINK IT'S <em>D.</em><em>.</em><em>.</em><em>.</em>
<em>HOPE </em><em>SO</em>
Energy travels with sound waves.
Answer:
0.3384 N
Explanation:
Acceleration = 13 m/s^2
Force = 4.4 N
Force = mass * acceleration
mass = force / acceleration
mass = 4.4 / 13
mass = 0.3384 N
The equation of motion of a pendulum is:

where
it its length and
is the gravitational acceleration. Notice that the mass is absent from the equation! This is quite hard to solve, but for <em>small</em> angles (
), we can use:

Additionally, let us define:

We can now write:

The solution to this differential equation is:

where
and
are constants to be determined using the initial conditions. Notice that they will not have any influence on the period, since it is given simply by:

This justifies that the period depends only on the pendulum's length.
B.Electromagnetic
explanation: