# What causes a horizontal force in a door supported by two hinges?

• oduracer
In summary, the door is supported by two hinges, one near the top and one near the bottom. Each hinge supports half of the door's weight, resulting in a balance of forces. The horizontal force on the door is caused by the torque from the hinges, as demonstrated by imagining what would happen if only one hinge were attached. Both hinges have to pull and push the door to properly support its weight.
oduracer
Problem:
A door of width 1.02 m and height 1.90 m weighs 288 N and is supported by two hinges, one a distance 0.500 m from the top and the other a distance 0.500 m from the bottom. Each hinge supports half the total weight of the door.

I'm not asking to solve this problem, I just need someone to explain how there would be any horizontal force at all, is this from the torque? When I try to draw a diagram, from what I can make of it, is that the forces exerted on the hinges are vertical. I just need clarification on the horizontal force.

Think about what would happen to the door if only the bottom hinge were attached. Then think about if only the top hinge were attached and the lower door frame was not in the way.

that makes sense now, the hinge would be pulling the door toward the hinge and holding it up at the same time. Is that correct?

oduracer said:
that makes sense now, the hinge would be pulling the door toward the hinge and holding it up at the same time. Is that correct?

The top hinge has to pull the door. The bottom hinge has to push it. And if the door is hung properly, both hinges support about the same weight.

OlderDan,
thank you very much for the help, I appreciate it a lot!

## 1. What is the concept of equilibrium in physics?

Equilibrium in physics refers to a state in which all the forces acting on an object are balanced, resulting in no net force and no acceleration. This means that the object remains at rest or moves with a constant velocity.

## 2. How is equilibrium related to the free body problem?

The free body problem is a mathematical representation of an object in equilibrium, where all the forces acting on the object are represented by vectors. By solving this problem, we can determine the unknown forces acting on the object and whether it is in equilibrium or not.

## 3. What are the conditions for an object to be in equilibrium?

An object is in equilibrium when the sum of all the forces acting on it is equal to zero, and the sum of all the torques (rotational forces) acting on it is also equal to zero. This means that the object is either at rest or moving with a constant velocity.

## 4. What are the different types of equilibrium?

There are three types of equilibrium: stable, unstable, and neutral. In stable equilibrium, the object returns to its original position after being displaced. In unstable equilibrium, the object moves away from its original position after being displaced. In neutral equilibrium, the object remains in its new position after being displaced.

## 5. How is the concept of equilibrium used in real-life applications?

The concept of equilibrium is used in various fields such as engineering, architecture, and biomechanics. It helps in designing structures and machines that can withstand different forces and remain in equilibrium. It is also used in understanding the stability of objects in different situations, such as balancing a seesaw or designing a suspension bridge.

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