Answer:
Objects between the source and observer produce possible shadows known as the umbra and the penumbra.
The umbra is a totally shadowed area, no light travels directly from the source to the observer.
The penumbra is a partially shadowed are where some of the source light travels directly to the observer an some of the source light is blocked from the observer (the object blocking the light is not a point object).
The question apparently refers to the differences seen by the observers.
Answer:
M1 = 16.9 mA
M2 = 0 A
Explanation:
As the ratio of the two sets of series resistors is almost exactly identical, there is no voltage difference across M2 to cause current flow
269/(269 + 439) = 0.3799...
500/(500 + 815) = 0.38022
M2 = 0
M1 sees only the current flowing through the far left resistors in series
A = V/R = 12/(269 + 439) = 0.016949... ≈ 16.9 mA
Answer:
B).315mph
Explanation:
Let the speed of the plane = p
Let the speed of the wind = w
Set up the system equation as;
Relative V: Time: Distance:
in wind direction: p + w 2 700
against wind: p - w 2.5 700
2(p + w) = 700
2.5(p - w) = 700
2p + 2w = 700
2.5p - 2.5w = 700
2.5 x: 5p + 5w = 1750
2 x: 5p - 5w = 1400
10p = 3150
p = 315 mph
Therefore, he speed of the plane in still air is 315 mph
