||Homework Help||Kindergarten-University. - Page 57

thnks sooo much you helped alot i really appreciate it 😊

Originally posted by: akhl

So all done 😊

Why do we use model organisms to study human nervous system? Explain in detail. Give organisms.

^ Akhl I tried finding a good website that possibly could have the answer to your question.

@Ayeshaa
Thank you. I needed that to help a student in Hawaii. I had already sent her some answer but was looking for more detail. I have sent her the links you gave.

@Sweet_Shivani
1. Inc. conc. of HCl
Explanation - When concentration of one side of reaction increases, then the equilibrium shifts to the other side, which means the concentration of the other side wil also increase. Cl2(g) and HntCl(g) are on different sides. Therefore increase in conc. of Cl2 increases the conc. of HCl

"Inc. the concentration of H2" is wrong because H2 and Cl2 are on the same side of the reaction.

Both sides, the number of moles of gaseous compounds is the same. Therefore, no change in pressure.

i need help...4 my project i have been reserching and asking on yahoo but no one answers and i cant find anything on this...pls help me someone!

Question :Blood flow rates can be found by measuring the Dopplers shift in frequency of ultrasound reflected by red blood cells. Assume that the speed of red blood cells is v, the speed of sound in blood is u, that the ultrasound emits sound of frequency f, and that the blood cells are moving directly towards the ultrasound source:

Originally posted by: Miggi

Question :Blood flow rates can be found by measuring the Dopplers shift in frequency of ultrasound reflected by red blood cells. Assume that the speed of red blood cells is v, the speed of sound in blood is u, that the ultrasound emits sound of frequency f, and that the blood cells are moving directly towards the ultrasound source:

a) Show that frequency of fr of the reflected reflected waves is given by fr = f[(1+v/u)/ (1-v/u)]

b) the reflected sound interferes with emitted sound producing beats. Find the beat frequency between the outgoing and reflected sound wave and show that it is proportional to the speed of the blood cell if v/u<1.

c) Say the ultrasound frequency used is 5.5MHz and the speed of sound in 1520m/s. If the beat frequency is 623Hz , what is the speed of the blood?

a) For the outgoing wave:-
Speed of source = 0
Speed of observer = v
The observer is moving towards the source

Therefore, the frequency observed by red blood cells is f1 where
f1 = f(u + v)/u
f1 = f(1 + v/u)

For the reflected wave, the red blood cells act as source and the ultrasound source acts as observer
Speed of source = v
speed of observer = 0
Source is moving towards observer

Therefore fr = f1 * u/(u - v)
fr = f1 * 1/(1 - v/u)
Substituting the value of f1,
fr = f [(1 + v/u) / (1 - v/u)]


b) Beat frequency = fr - f
= f [(1 + v/u) / (1 - v/u)] - f
= f (2v/u) / (1 - v/u)
= 2f (v/u) / (1 - v/u)
If v/u << 1, then
beat frequency = 2f (v/u), which is proportional to v

c) f = 5.5 * 10^6 Hz
Beat freuency = 2f (v/u)
623 = 2 * 5.5 * 10^6 * (v/1520)
v = 0.0861 m/s
v = 8.61 * 10^-2 m/s (Answer)