The wavelength of the third resonance of the closed organ pipe is equal to the ratio between the speed of sound and the frequency of the 3rd harmonic:

The relationship between length of a closed pipe and wavelength of the standing waves inside is:

where n is the number of the harmonic. In this case, n=3, so the length of the pipe is

Answer:
B. Direction
Explanation:
Speed is a scalar quantity and doesn't keep track of direction : Velocity is a vector quantity and is direction aware.
Answer:
V = 0.39 m/s
Explanation:
Given that,
Mass of hockey puck, m = 0.2 kg
Mass of goalie = 40 kg
Speed of hockey puck, v = 80 m/s
We need to find the speed with which the goalie slide on the slide. Let V be the speed. Using the conservation of momentum as follows :

So, the required speed is 0.39 m/s.
Treatment water from the plant would affects the communities present in the downstream of the river.
Answer: Option (a)
<u>Explanation:</u>
Wastewater treatment plant is a process used to treat the water that flows from the rivers, streams, and lakes.This plant removes the dust, sand, sediments present in the river water.
When this treated water is released into the downriver stream, it affects the health of aquatic organisms present in that stream.Use of chemicals in treating the wastewater may cause genetic problems to the communities present in that region.
It also causes air pollution and more energy is needed for the treatment process and thus affects the ecosystem.
They would only know the width of the window. A floor plan is like a top down view of a building. Imagine that you cut your house in half horizontally, and then looked down at it. All you would see would be the width of the windows, not the height or anything else.