How to find the coefficient of friction in a rotor-ride?

In summary, the conversation discusses defining the coefficient of friction (mu) in terms of variables such as mass, velocity, and radius in order to determine the minimum value needed to keep people pinned against the wall on a moving carousel. The attempt at a solution involves using equations for centripetal force, friction, and gravity to derive the formula mu=(gr)/(v^2). However, it is noted that this solution does not involve a square root, which is included in the answer choices.
  • #1
broadwayboo
1
0

Homework Statement


I have no values at all, so it's just going to be the variables in the relevant equations. I need to define mu using those variables.
A carousel is moving in a circle at velocity v and has a radius r. It is moving fast enough that each person with mass m is pinned against the wall and not moving. What does mu (the coefficient of friction) have to be in order for the people to not move? Define it in terms of m, g, r, or v.
I know that it has a square root involved somewhere because all the answer choices have square roots.

Homework Equations


friction=mu(normal force)
centripetal Force= mv^2/r
Force of Gravity=gm

The Attempt at a Solution


Centripetal force=normal force=force of friction/ mu
force of friction/ mu=mv^2/r
force of friction= force of gravity (because friction pushes up with the same amount as gravity pushes down)
mg/ mu= mv^2/r
g/ mu =v^2/r
(cross multiply)
mu*v^2= gr
mu=(gr)/(v^2)
But I know this can't be right because there's no square root.
 
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  • #2
Hi b! http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif

What are the answer choices offered?
 
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Related to How to find the coefficient of friction in a rotor-ride?

1. What is the coefficient of friction in a rotor-ride?

The coefficient of friction in a rotor-ride is a measure of the amount of friction between the rotor and the ride surface. It is a dimensionless quantity that describes the ratio of the force of friction to the normal force between the two surfaces.

2. Why is it important to find the coefficient of friction in a rotor-ride?

Knowing the coefficient of friction in a rotor-ride is important for safety and efficiency purposes. It helps determine the amount of force needed to rotate the rotor, and it also affects the speed and smoothness of the ride.

3. How do I calculate the coefficient of friction in a rotor-ride?

The coefficient of friction can be calculated by dividing the force of friction by the normal force. The force of friction can be measured using a force sensor, and the normal force can be calculated by multiplying the mass of the rotor by the acceleration due to gravity.

4. What factors can affect the coefficient of friction in a rotor-ride?

The coefficient of friction can be affected by various factors such as the type and condition of the ride surface, the weight and shape of the rotor, the speed of rotation, and the presence of any lubricants or coatings on the surfaces.

5. Can the coefficient of friction in a rotor-ride change over time?

Yes, the coefficient of friction in a rotor-ride can change over time due to factors such as wear and tear on the surfaces, changes in temperature, and the buildup of debris or moisture on the surfaces. It is important to regularly monitor and adjust the coefficient of friction to ensure the safety and efficiency of the ride.

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