Answer:
Your answer should be A. 0.25 J and moving to the right
Explanation:
The radio frequencies push one air molecule that then bumps into a different air molecule.....which then hits another and another causing a line of crashing molecules that lead inside your ear and hits your ear drum causing it to vibrate which causes the sounds.
Answer:
19.95 J
Explanation:
The center of mass of the ladder is initially at a height of:

The center of mass of the ladder ends at a height of:
=L/2
So, the work done is equal to the change in potential energy which is:
W = PE = 
now 
therefore
W = [mgL/2]×[1 - sin(theta)]
W = [(7.30)(9.81)(2.50)/2]×[1-sin(51°)]
solving this we get
W = 19.95 J
Resistance = (voltage) / (current)
Resistance = (100 V) / (20 A)
<em>Resistance = 5 Ω (D)</em>

for a solid cylinder:

for a hollow cylinder:

I will look at the case of a hollow cylinder:

That is as far as i get.