D. lenses focus light , mirrors do not
I believe that the answer is B. 133 N
Well, Air resistance is a special type of friction (you cannot classify it in other categories). That force of air-resistance is often observed to oppose the motion of the object,( like every other frictional forces)
Hope this helps!
For this case, the switch is located at point B of the diagram.
Remember that point D is the universal symbol for resistance.
In A what you have is a source of power and in C what you have is a cable.
Therefore, the answer for this case is B.
If the two waves combine to produce ANY wave that smaller
than either of the originals, that's destructive interference.
