The Correct Answer is <u>D.Infrared/</u> <em>INFARED has a lower frequency than visible light/</em>
Answer: 93ft
Explanation: Martha's eyesight make an angle with the fence, this is solved as a triangle problem.
We first convert all the dimensions to inches using the fact that 12 inches make 1 ft.
To solve for the angle
Tan § = 18/48 = 0.375
§ = tan^-1 of 0.375 = 20.55°
This same angle elevates to the edge of the building
Tan 20.55 = 399/x
x = 399/tan 20.55
x = 1040 inches
Height of building = x + height of fence
Height of building = 1040 + 78 = 1118 inches
Converting back to ft it becomes
1118/12 = 93 ft 2 inches
Approximately 93ft
Divide 225 / 25
225/25= 9
Derek will read the article in 9 minutes.
When the interfering waves have an amplitude of zero the phenomena is called destructive interference.
It occurs when waves come together in such a way that they completely cancel each other out. When two waves interfere destructively, they must have the same amplitude in opposite directions it means that the waves are in 180° different phase from each other.
I’m not Vietnamese but I think your asking for this, for people who understand Vietnamese pls help them :d