Need help with centripetal acceleration problem.

In summary, a biophysicist is using an analytic ultracentrifuge to separate sub-cellular particles and needs to determine the magnitude of the centripetal acceleration at a specific speed and radius. Using the formula ac = 4pi^2rf^2, the biophysicist calculates the centripetal acceleration to be 3.32 x 10^7 m/s^2. To express the answer in terms of g, the biophysicist divides the acceleration by the acceleration due to Earth's gravity, resulting in 3.39 x 10^6 m/s^2. However, it should be noted that the radius used in the calculation should be 0.084m instead of 0.
  • #1
Imperil
39
0
PROBLEM
A biophysicist wants to separate sub-cellular particles with an analytic ultracentrifuge. The biophysicist must determine the magnitude of the centripetal acceleration provided by the centrifuge at various speeds and radii.

Calculate the magnitude of the centripetal acceleration at 8.4cm from the centre of the centrifuge when it is spinning at 6.0 x 10^4rpm. Express your answer in terms of g (acceleration due to Earth's gravity).

MY ANSWER
r = 0.84m
f = 6.0 x 10^4rpm = 1000s

ac = 4pi^2rf^2
= 4pi^2(0.84m)(1000s)^2
= 3.32 x 10^7 m/s^2

So now that I have the centripetal acceleration I'm unsure of how to express my answer in terms of g as per the second part of the question. What I did was the following:

ac / g
3.32 x 10^7 m/s^2 / 9.8 m/s^2 = 3.39 x 10^6 m/s^2

but I am second guessing this because I really have no idea why I dividedt he acceleration by the acceleration of Earth's gravity. Could somebody shed some light on this and if I am wrong?
 
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  • #2
ac / g
3.32 x 10^7 m/s^2 / 9.8 m/s^2 = 3.39 x 10^6 m/s^2

You have to wright the answer as
(ac / g)*g
3.32 x 10^7 m/s^2 / 9.8 m/s^2 = (3.39 x 10^6 )g. That is whar required.
 
  • #3
Imperil said:
Express your answer in terms of g (acceleration due to Earth's gravity).

ac = 4pi^2rf^2
= 4pi^2(0.84m)(1000s)^2
= 3.32 x 10^7 m/s^2

So now that I have the centripetal acceleration I'm unsure of how to express my answer in terms of g as per the second part of the question. What I did was the following:

ac / g
3.32 x 10^7 m/s^2 / 9.8 m/s^2 = 3.39 x 10^6 m/s^2

but I am second guessing this because I really have no idea why I dividedt he acceleration by the acceleration of Earth's gravity. Could somebody shed some light on this and if I am wrong?

Some light has already been shed, but I'm just asking you this simple question: if ac was equal to, say, 4.1*9.8 m/s^2, how much would it be in terms of g?
 
  • #4
Bro...The QUestion Stated that r=8.4cm, so r=0.084m not r=0.84m...Correct that and so u r answer would be one decimal off...right answer would be ac= 3.32*10^6...in terms of g = 3.39*10^5 no unit.
 

Related to Need help with centripetal acceleration problem.

1. What is centripetal acceleration?

Centripetal acceleration is the acceleration that an object experiences as it moves in a circular path. It is always directed towards the center of the circle and is responsible for keeping the object moving in a curved path.

2. How do you calculate centripetal acceleration?

The formula for calculating centripetal acceleration is a = v2/r, where a is the centripetal acceleration, v is the velocity of the object, and r is the radius of the circular path.

3. What units are used to measure centripetal acceleration?

Centripetal acceleration is typically measured in meters per second squared (m/s2).

4. What factors affect centripetal acceleration?

Centripetal acceleration is affected by the speed of the object, the radius of the circular path, and the mass of the object. The higher the speed and the smaller the radius, the greater the centripetal acceleration will be.

5. How is centripetal acceleration related to centripetal force?

Centripetal acceleration and centripetal force are related by Newton's second law of motion, which states that force is equal to mass times acceleration (F=ma). In the case of centripetal motion, the centripetal force is provided by the centripetal acceleration, and it is directed towards the center of the circular path.

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