A progressive wave equation is represented by y=Asin 2π(0.15t-0.1x). find the period

y=Asin 2π(0.15t-0.1x)

At some time t and coordinate x let  (0.15t-0.1x) = n  where n is an integer.

y will be zero

At a later time and the same value of x

(0.15(t + P)-0.1x) = n +1   where P is the period ;  y again will be zero

(0.15(t + P)-0.1x) = n +1

(0.15t-0.1x) = n

.015 P = 1        subtracting equations

P = 1 / .15 = 6.67 sec

the assestment will probley apele with cause and effect

as we know our atmosphere or air have different levels. every level has other gasses, and every gas has another permeability. when the light comes from lower permeability to higher permeability, it changes its direction. so that means that when the light comes from the moon to the earth, it changes it's direction many more times. it basically means that the shape of the light part of the moon is changed on the earth.

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