Finding minimum angular speed? in rpms

In summary, the conversation is about finding the minimum angular speed, in rpm, for an old-fashioned amusement park ride to be safe. The ride involves passengers standing inside a rotating steel cylinder with a sudden drop in the floor. The ride has a weight limit and the coefficient of friction between clothing and steel is mentioned. The conversation also includes questions about the forces and frictional force involved in finding the minimum speed.
  • #1
dubsydub14
2
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Finding minimum angular speed?? in rpms

In an old-fashioned amusement park ride, passengers stand inside a 5.5-m-diameter hollow steel cylinder with their backs against the wall. The cylinder begins to rotate about a vertical axis. Then the floor on which the passengers are standing suddenly drops away! If all goes well, the passengers will "stick" to the wall and not slide. Clothing has a static coefficient of friction against steel in the range 0.61 to 1.0 and a kinetic coefficient in the range 0.40 to 0.70. A sign next to the entrance says "No children under 30 kg allowed."

What is the minimum angular speed, in rpm, for which the ride is safe?

I know i need an equation that relates mass and the coefficiant frictions to the angular speed but I am having no such luck

any feedback or help would be greatly appreciated
 
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  • #2


What forces are going to be acting on the passengers?

How does the coefficient of friction play into finding the frictional force?

These questions should get you started on getting an answer.
 
  • #3


Thank you for your question. In order to find the minimum angular speed for the ride to be safe, we need to consider the forces acting on the passengers and the maximum friction force that can be exerted by the clothing. The equation we can use is the centripetal force equation:

F = mv^2/r

Where F is the centripetal force, m is the mass of the passenger, v is the tangential velocity, and r is the radius of the cylinder. We can rearrange this equation to solve for the tangential velocity:

v = √(Fr/m)

We also know that the maximum friction force is equal to the coefficient of static friction multiplied by the normal force, which in this case is the weight of the passenger (mg). The equation for maximum friction force is:

Ffmax = μs mg

Where μs is the static coefficient of friction. We can substitute this into our equation for tangential velocity:

v = √(μs mg r/m)

Now, we need to determine the minimum angular speed, which is equivalent to the tangential velocity divided by the radius of the cylinder. This gives us the equation:

ωmin = v/r = √(μs g)

Where g is the acceleration due to gravity (9.8 m/s^2). We can then convert this angular speed to rpm by dividing by 2π radians and multiplying by 60 seconds:

ωmin (in rpm) = (√(μs g) / 2π) * 60

Using the given range of coefficients of friction (0.61 to 1.0), we can calculate the minimum angular speed to be in the range of 7.8 to 9.6 rpm. Therefore, for the ride to be safe, the minimum angular speed should be at least 7.8 rpm. However, it is always recommended to have a higher angular speed for added safety. I hope this helps!
 

1. What is the formula for finding minimum angular speed in rpms?

The formula for finding minimum angular speed in rpms is given by: minimum angular speed = 2π * rpm / 60, where π is the mathematical constant pi and rpm is the revolutions per minute.

2. How is minimum angular speed related to linear speed?

Minimum angular speed and linear speed are directly proportional. This means that as minimum angular speed increases, linear speed also increases. The relationship between the two can be described by the formula: linear speed = minimum angular speed * radius, where radius is the distance from the center of rotation to the object.

3. What factors affect the minimum angular speed of an object?

The minimum angular speed of an object can be affected by several factors, including the radius of rotation, the mass of the object, and any external forces acting on the object. The shape and distribution of mass of the object can also influence its minimum angular speed.

4. How can I measure minimum angular speed in rpms?

To measure minimum angular speed in rpms, you will need to know the number of revolutions completed by the object in one minute. This can be measured using a tachometer, which is a device that measures the number of revolutions per minute of an object.

5. Why is it important to find the minimum angular speed of an object?

Finding the minimum angular speed of an object is important because it allows us to understand and predict the behavior of the object in circular motion. It also helps us determine the amount of force required to keep the object in motion and to prevent it from slipping or flying off its circular path.

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