Answer:
A. Air
Explanation:
A thermal insulator is a material that does not let the heat trasmitting through it, or it transmits heat not very efficiently.
Generally, the lower the density of the material, the better insulator the material is: this is because in materials with very low density, particles are very spread apart, so they cannot collide with each other, and so the vibrations of the particles (which determine how hot a substance is) cannot be transmitted very efficiently.
In the options listed in this problem, air is the material with lowest density, therefore it is the best thermal insulator among them.
Answer:
The length is
and the angle is 
Explanation:
The period
of the pendulum is related to its length
by

where
is the acceleration due to gravity.
Solving for
we get

putting in
and
we get:


There are two forces acting on the pendulum: The gravitational force
and the
student's force. Therefore, the angular displacement
that these forces give is


putting in
,
, and
we get


Answer:
The statement of the student is correct.
Since B attained a higher velocity in a short amount of time, that is it accelerated faster(having a larger slope).
Slope = dy/dx
That is, <u>Velocity</u>
Time
which is acceleration.
That's my guess.
Hope it's right.
<span>The hypothesis must be testable and falsifiable. The first stipulation is that the hypothesis must be able to be tested and be phrased as such. In addition, the second stipulation holds that the statement must be able to be falsified; that is, the statement can be showed to not be the case.</span>
Answer:
v = 8.4 m/s
Explanation:
The question ays, "A longitudinal wave has a frequency of 200 Hz and a wavelength of 4.2m. What is the speed of the wave?".
Frequency of a wave, f = 200 Hz
Wavelength = 4.2 cm = 0.042 m
We need to find the speed of the wave. The formula for the speed of a wave is given by :

So, the speed of the wave is equal to 8.4 m/s.