Question about a Rotor Ride in a amusement park

  • B
  • Thread starter bonbon1
  • Start date
  • Tags
    Rotor
In summary, the maximum static friction force occurs when an object is on the verge of sliding and is proportional to the normal force with a constant of proportionality being the coefficient of static friction. In a situation where the normal force changes, the maximum possible force of static friction also changes. However, the actual force applied will only be as much as is needed to prevent sliding. This explains why the person in a rotor can remain stuck to the wall even as the normal force and maximum possible static friction force change due to changes in angular velocity.
  • #1
bonbon1
4
1
Hi
I don't understand why the static friction force is maximum in this situation?View attachment rotor1.jpg
 
Last edited:
Physics news on Phys.org
  • #2
Because you are looking for the minimum coefficient of static friction, i.e. the person is just on the verge of sliding.
 
  • Like
Likes bonbon1
  • #3
kuruman said:
Because you are looking for the minimum coefficient of static friction, i.e. the person is just on the verge of sliding.

ok thank you. Is there also a mathematical explanation for that?
 
  • #4
bonbon1 said:
ok thank you. Is there also a mathematical explanation for that?
No. There is a mathematical formulation based on a physical event that can be described in plain English. The event is that the person is about to start sliding in which case the force of static friction has reached its maximum value which is proportional to the normal force, the constant of proportionality being the coefficient of static friction. All that wording can be formulated in shorthand mathematical notation as ##f_s^{max}=\mu_sN##. It's a much more compact way of saying the same thing and that's why we use math when we do physics.
 
  • #5
kuruman said:
No. There is a mathematical formulation based on a physical event that can be described in plain English. The event is that the person is about to start sliding in which case the force of static friction has reached its maximum value which is proportional to the normal force, the constant of proportionality being the coefficient of static friction. All that wording can be formulated in shorthand mathematical notation as ##f_s^{max}=\mu_sN##. It's a much more compact way of saying the same thing and that's why we use math when we do physics.
and if there is a situation in which a person is in a rotor and the angular velocity changes (and then as a result, the normal force changes) and the person is still stucked to the wall, is it affect the fs or just the fsmax?
 
Last edited:
  • #6
bonbon1 said:
and if there is a situation in which a person is in a rotor and the angular velocity changes (and then as a result, the normal force changes) and the person is still stucked to the wall, is it affect the fs or just the fsmax?
To be clear, we have the person in a rotor and they are just on the verge of sliding down. The force of static friction is exactly equal to the maximum force of static friction. But now the rotor speeds up. The normal force increases.

1. Because the normal force has increased, the maximum possible force from static friction has increased.

2. If it only takes a frictional force of magnitude mg to support the person, it still only takes that much frictional force no matter how fast the rotor spins. The actual frictional force will be only as much as is required, not as much as could possibly be provided.

If, on the other hand the rotor slows down then the normal force decreases.

1. Because the normal force has decreased, the maximum possible force from static friction has decreased.

2. If it takes a frictional force of magnitude mg to support the person and the maximum force of static friction is less than that then the actual force from static friction will be equal to the maximum and the person is doomed to slip downward.
 
Last edited:
  • Like
Likes berkeman and bonbon1
  • #7
jbriggs444 said:
To be clear, we have the person in a rotor and they are just on the verge of sliding down. The force of static friction is exactly equal to the maximum force of static friction. But now the rotor speeds up. The normal force increases.

1. Because the normal force has increased, the maximum possible force from static friction has increased.

2. If it only takes a frictional force of magnitude mg to support the person, it still only takes that much frictional force no matter how fast the rotor spins. The actual frictional force will be only as much as is required, not as much as could possibly be provided.

If, on the other hand the rotor slows down then the normal force decreases.

1. Because the normal force has decreased, the maximum possible force from static friction has decreased.

2. If it takes a frictional force of magnitude mg to support the person and the maximum force of static friction is less than that then the actual force from static friction will be equal to the maximum and the person is doomed to slip downward.
Thank you! Now I understand
 
  • Like
Likes berkeman

1. How does a rotor ride work?

The rotor ride is a spinning amusement park ride that uses centrifugal force to keep riders pressed against the walls of the ride. The ride consists of a circular platform with angled walls and a central axis. As the ride spins, the walls rise and riders are pressed against them due to the outward force.

2. Is the rotor ride safe?

Yes, the rotor ride is designed and regularly inspected to ensure safety for riders. The walls of the ride are padded and the ride is equipped with safety restraints to keep riders secure. However, it is important to follow all safety guidelines and instructions provided by the ride operator.

3. How fast does the rotor ride spin?

The speed of the rotor ride can vary, but it typically spins at a speed of 10-15 revolutions per minute. This speed is enough to create the centrifugal force needed to keep riders pressed against the walls, but not too fast to cause discomfort.

4. What is the maximum weight limit for the rotor ride?

The maximum weight limit for the rotor ride can vary depending on the specific ride and its design. However, most rotor rides have a weight limit of around 300-350 pounds per rider. It is important to follow all weight restrictions for safety reasons.

5. Are there any health restrictions for riding the rotor ride?

Yes, there may be health restrictions for riding the rotor ride, such as those with heart conditions, back problems, or pregnant women. It is important to check with the ride operator or read the warning signs before riding to ensure your safety.

Similar threads

  • Introductory Physics Homework Help
Replies
8
Views
341
  • Electrical Engineering
Replies
3
Views
823
  • Engineering and Comp Sci Homework Help
Replies
3
Views
913
  • Advanced Physics Homework Help
Replies
2
Views
1K
  • Classical Physics
Replies
2
Views
848
Replies
20
Views
2K
Replies
1
Views
549
Replies
17
Views
788
Replies
10
Views
2K
  • Aerospace Engineering
Replies
7
Views
4K
Back
Top