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<span>Hormone: a chemical message released in the bodyby cells and glands that affects other cells in an organism. Hypothalamus: a part of the brain thatcontrols things like thirst, hunger, body temperature, and the release of many hormones.</span>
Answer:
Velocity, v = 0.239 m/s
Explanation:
Given that,
The distance between two consecutive nodes of a standing wave is 20.9 cm = 0.209 m
The hand generating the pulses moves up and down through a complete cycle 2.57 times every 4.47 s.
For a standing wave, the distance between two consecutive nodes is equal to half of the wavelength.

Frequency is number of cycles per unit time.

Now we can find the velocity of the wave.
Velocity = frequency × wavelength
v = 0.574 × 0.418
v = 0.239 m/s
So, the velocity of the wave is 0.239 m/s.
A sample of nitrogen gas has a volume of 5.0 ml at a pressure of 1.50 atm. what is the pressure exerted by the gas if the volume increases to 30.0 ml, at constant temperature is 0.25atm.
On constant temperature, the pressure and volume relation become constant before and after the change in quantitities have occurred.
According to Boyle's Law,
P₁V₁ = P₂V₂
where, P₁ is pressure exerted by the gas initially
V₁ is the volume of gas initially
P₂ is pressure exerted by the gas finally
V₂ is the volume of gas finally
Given,
P₁ = 1.5 atm
V₁ = 5 ml
V₂ = 30 ml
P₂ =?
On substituting the given values in the above equation:
P₁V₁ = P₂V₂
1.5 atm × 5 ml = P₂ × 30 ml
P₂ = 0.25 atm
Hence, pressure exerted by the gas is 0.25atm.
Learn more about Boyle's Law here, brainly.com/question/1437490
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It’s b all objects with mass experience gravitational attraction I hope this helps