Answer: 4.17m
Explanation:
The observer at C will hear a sound on no sound upon whether the interference is constructive or destructive.
If the listeners hears sounds it is caled constructive interference but if he hears no sound its called destructive interference.
So
d2 - d1 = (n *lamba)/ 2
Where n=1,3,5
lamda=v/f =349/62.8
lamda=5.56m
d2= d1 + nlamda/2
d2= 1 + 5.56/2
d2= 3.78m
X'= 1 cos 60= 0.5m
Y= 1 sin60= 0.866m
X"^2 + Y^2 =d2^2
X" =√(y^2 - d2^2)
X"=√(3.78^2 - 0.886^2)
X"= 3.67m
So therefore the closest that speaker A can be to speaker B so the listener does not hear any sound is X' + X"= 0.5 + 3.67
4.17m
The correct answer is:
D. Extrusive rocks.
The explanation:
when extrusive igneous rocks form when magma reaches the Earth's surface a volcano and cools quickly. Most extrusive (volcanic) rocks have small crystals. Examples include basalt, rhyolite, andesite, and obsidian.
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The two kinds of motion are horizontal and vertical