Seesaw physics and center of mass

In summary, the conversation is about creating a program that simulates the physics of a seesaw. The goal is to find an equation that can determine the rotation speed of the seesaw based on the masses on each end. The solution involves using Newton's second law for circular motion and taking into account the weight, polar moment of inertia, and torque. The equation can also account for friction and air resistance if desired.
  • #1
2DGamer
8
0
I want to write a program that basically mimics the physics of seesaws. Part of a project I'm working on. I understand how equilibrium works and everything, but let's say that I have a mass on each end of the seesaw, and both masses are equal distance from the pivot. If both masses have the same mass then the seesaw would be in equilibrium and the seesaw would be horizontal. But, what if one of the masses is heavier than the other? The center of mass would be shifted towards the heavier mass and the seesaw would start to rotate since the center of mass applies a torque. I'm just trying to find an equation that will tell me how fast it's rotating depending on the masses. I broke out my old physics book, but the equations I'm coming up with aren't working. Maybe there's just something I'm missing. Are there 3 torques from the two ends and center of mass or just the center of mass torque? can I use the moment of inertia here or is it not necessary? Any help would be greatly appreciated.
 
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  • #2
Assuming the see-saw is anchored in the middle, apply Newtons second law for circular motion. That is the total rotating moment( force x arm) = polar moment of inertia x angular acceleration. The net force is weight(gravity force with direction taken correctly) x arm . Integrating this gives you angular velocity and integrating again gives you angular displacement . This works for any masses and is a standard problem in mechanics. You can include the torque due to friction in the anchor and due to moving in air if you want too.
 

Related to Seesaw physics and center of mass

1. What is a seesaw and how does it work?

A seesaw is a simple playground equipment consisting of a long plank balanced on a fulcrum or pivot point. The seesaw works by utilizing the principles of physics, specifically the concept of the center of mass. When two people of different weights sit on opposite ends of the seesaw, the heavier person will lower the end they are sitting on, causing the lighter person to rise. This is because the heavier person's weight is closer to the fulcrum, creating a larger moment and tilting the seesaw in their direction.

2. What is the role of the center of mass in seesaw physics?

The center of mass is the point on an object where its mass is equally distributed in all directions. In the case of a seesaw, the center of mass is where the plank balances on the fulcrum. The position of the center of mass determines which end of the seesaw will be lower when weight is applied, and thus, which end will move.

3. Can the center of mass be outside of the object?

Yes, the center of mass can be outside of the object. This is because the center of mass is a theoretical point that represents the distribution of mass in an object, and it does not have to correspond to an actual physical point on the object.

4. How does the position of the center of mass affect the stability of a seesaw?

The position of the center of mass plays a crucial role in the stability of a seesaw. For a seesaw to be stable, the center of mass must be directly above the fulcrum. If the center of mass is off-center, the seesaw will be unbalanced, and one end will be lower than the other. This can lead to the seesaw tipping over.

5. How can the center of mass be changed on a seesaw?

The center of mass of a seesaw can be changed by altering the weight distribution of the objects on either end. For example, if a heavier person moves closer to the fulcrum, the center of mass will shift in their direction. Additionally, the length of the seesaw plank can also affect the position of the center of mass. A longer plank will have a different center of mass than a shorter one.

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