Answer:
Their experimental design lacks control group
Explanation:
Based on what I read, the scientists don't have a control group as one of the main groups thus they cannot, in scientific sense, say that the medicine is better or worse. You always need a control group receiving no intervention because then we can compare groups and assess the effectiveness of that intervention (in our case if we had control group vs people who received the medicine, we could see if the people who received the medicine had improved condition etc when compared to participants who did not receive anything)
Answer:
773.25 Hz
Explanation:
Concept : In an open organ pipe in fundamental mode of vibration
wave length of wave λ = 2L
where L is length of the pipe
frequency = velocity of sound / λ
Given values: fundamental frequency = 288 Hz
fluid is air. velocity of sound = 340 m/s
⇒ 288 = 340/2L
⇒L = 59.02 cm
The point to be noted is if the pipe is filled with helium initially at the same temperature, there would be change in the sound velocity .Then, frequency of note produced will also be changed .
We know that velocity of sound is inversely proportional to square root of molar mass of gas
velocity of sound in air / velocity of sound in helium = Square root of (Molar mass of Helium/ molar mass of air)
Now, frequency = velocity of sound / λ
= 912.75 / (2 x 0.5902)
= 773.25 Hz
<h2>Answer::</h2>
Humans (biosphere) built a dam out of rock materials (geosphere). Water in the lake (hydrosphere) seeps into the cliff walls behind the dam, becoming groundwater (geosphere), or evaporating into the air (atmosphere).','.
Answer:
as they go from solid to liquis to gas they heat up from thermal energy. that thermal energy then excites the molecules making them move faster causing them to change phases.
