Since it is restricted at both ends, λ/2 = length of string
λ/2 = 1.5m
λ = 1.5*2 = 3m
Answer:
option C (1 and 4)
Explanation:
Like poles repel each other, unlike poles attract each other
The change in momentum of an object equals the impulse applied to it
First choice: the inability of current technology to capture
large amounts of the
Sun's energy
Well, it's true that large amounts of it get away ... our 'efficiency' at capturing it is still rather low. But the amount of free energy we're able to capture is still huge and significant, so this isn't really a major problem.
Second choice: the inability of current technology to store
captured solar
energy
No. We're pretty good at building batteries to store small amounts, or raising water to store large amounts. Storage could be better and cheaper than it is, but we can store huge amounts of captured solar energy right now, so this isn't a major problem either.
Third choice: inconsistencies in the availability of the resource
I think this is it. If we come to depend on solar energy, then we're
expectedly out of luck at night, and we may unexpectedly be out
of luck during long periods of overcast skies.
Fourth choice: lack of
demand for solar energy
If there is a lack of demand, it's purely a result of willful manipulation
of the market by those whose interests are hurt by solar energy.
Answer:
<em>a) 3.6 ft</em>
<em>b) 12.4 ft</em>
Explanation:
Distance between mirrors = 6.2 ft
difference from from the mirror you face = 1.8 ft
a) you stand 1.8 ft in front of the mirror you face.
According to plane mirror rules, the image formed is the same distance inside the mirror surface as the distance of the object (you) from the mirror surface. From this,
your distance from your first "front" image = 1.8 ft + 1.8 ft = <em>3.6 ft</em>
b) The mirror behind you is 6.2 - 1.8 = 4.4 ft behind you.
the back mirror will be reflected 3.6 + 4.4 = 8 ft into the front mirror,
the first image of your back will be 4.4 ft into the back mirror,
therefore your distance from your first "back" image = 8 + 4.4 = <em>12.4 ft</em>