# Rod is toppling. Find reaction force as a function of theta

• NucEngMajor
In summary, the conversation discusses a homework problem involving a rod of length b and mass m that topples from a vertical position at theta = 0. The question asks to calculate the reaction force f as a function of theta and determine its minimal and maximal values for theta between 0 and pi. The person asking the question admits to being unfamiliar with this type of mechanics problem and asks for the solution. A mention is made of using Lagrangians to solve the problem, and the topic of constraint forces and Lagrangian multipliers is brought up.
NucEngMajor

## Homework Statement

Rod of length b and mass m topples from vertical position at theta = 0. Calculate the reaction force f as a function of theta. What is the minimal and maximal values of f for theta between 0 and pi

Third law?[/B]

## The Attempt at a Solution

I never really worked a problem such a this in mechanics. So I was shocked to see this on my exam. I would like to know what the solution is. I had no idea how to solve. I suppose this falls under rigid body motion, but all we worked in that topic were lagrangians...

can the rod slip on the ground?

NucEngMajor said:
I suppose this falls under rigid body motion, but all we worked in that topic were lagrangians...
In general, exam questions are related to the material that's been presented. So you wrote a Lagrangian for this constrained system and found the equation of motion. Did you also learn that the constraint forces follow from the Lagrangian multipliers ?

## 1. What is meant by "Rod is toppling" in this context?

In this context, "Rod is toppling" refers to a physical phenomenon where a rod or object is in an unstable position and begins to fall or topple over due to an external force acting on it.

## 2. What does theta represent in the equation?

Theta (θ) represents the angle at which the rod is tilted or inclined from its stable position. It is also known as the angle of inclination.

## 3. How do you calculate the reaction force as a function of theta?

The reaction force can be calculated by using the equation: R = mg tan(θ), where R is the reaction force, m is the mass of the rod, g is the gravitational acceleration, and θ is the angle of inclination.

## 4. What factors can affect the reaction force?

The reaction force can be affected by the mass of the rod, the angle of inclination, and the gravitational acceleration. Other factors that can also affect the reaction force include the surface on which the rod is placed, the presence of external forces, and the material properties of the rod.

## 5. What is the significance of finding the reaction force as a function of theta?

Finding the reaction force as a function of theta allows us to understand the relationship between the angle of inclination and the stability of the rod. It also helps us to predict how much force is required to keep the rod in a stable position or prevent it from toppling over.

Replies
4
Views
2K
Replies
1
Views
254
Replies
7
Views
814
Replies
48
Views
8K
Replies
41
Views
3K
Replies
6
Views
478
Replies
3
Views
1K
Replies
12
Views
1K
Replies
39
Views
3K
Replies
1
Views
958