# Flag pole finding horizontal force component at hinge.

• Parker Hays
In summary, the conversation discusses a flag pole with a 80 kg rod and a 10 kg point mass attached to the end, hinged at the bottom and tied to a horizontal cable. The question is about finding the x-component of the force exerted by the wall on the flag pole at the hinged point A. The attempt at a solution involves finding the center of mass and considering the torque exerted by each force about a chosen axis.
Parker Hays

## Homework Statement

A flag pole consists of a 80 kg rod of length L = 2 m with a 10 kg point mass attached to the end. The pole is hinged at the bottom and is tied to a horizontal cable as shown.
1. What is the x-component of F (Fx) exerted by the wall on the flag pole at the hinged point A?
(The picture shows the flag pole hinged at a 30 degree angle to the horizontal and the 10kg point mass is not on the hinged side).

## Homework Equations

Net torque=0, Net force=0, τ=r x F=Iα.

## The Attempt at a Solution

I've attempted to find the location of the center of mass so that I can know where the gravity acts on the rod. I have gotten many different answers but none of them have been correct. The correct answer is 850N and I don't know how to get there, other than Fnet=0N and τnet=0Nm. I also think torque due to the hinge is zero since it is at the hinge and therefore r x F is zero.

#### Attachments

• finImg9.gif
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Parker Hays said:
attempted to find the location of the center of mass
That is rarely necessary.
Just consider the torque that each force exerts (about some chosen axis) and sum them.
To choose an axis, look at the forces you do not know and do not need to find. If you can pick an axis on the intersection of their lines of action you will only need the one equation.
Otherwise you will need both torque and linear equations.

CWatters

## What is a flag pole?

A flag pole is a tall, slender structure made of metal, wood, or fiberglass that is used to display flags. It typically has a cylindrical shape and is mounted vertically on a base.

## What is a hinge?

A hinge is a mechanical joint that allows two objects to rotate or move relative to each other. It typically consists of two plates with interlocking teeth that pivot around a pin or rod.

## Why is it important to find the horizontal force component at the hinge of a flag pole?

It is important to find the horizontal force component at the hinge of a flag pole because it helps determine the stability of the pole. If the horizontal force component is too great, it can cause the pole to tip over or put excessive stress on the hinge, potentially causing it to break.

## How is the horizontal force component at the hinge of a flag pole calculated?

The horizontal force component at the hinge of a flag pole can be calculated using the formula F = mg tanθ, where F is the horizontal force component, m is the mass of the flag pole, g is the gravitational acceleration, and θ is the angle of the pole from the vertical.

## What can affect the horizontal force component at the hinge of a flag pole?

The horizontal force component at the hinge of a flag pole can be affected by factors such as wind speed, the weight of the flag and the pole, the angle of the pole, and the stability of the base. Other external forces, such as seismic activity, can also impact the horizontal force component.

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