What is the moment experience by each hinges?

In summary, the moment experienced by each hinge is equal to the weight of the door multiplied by the distance between the hinges, divided by the total distance from the center of gravity of the door to the hinge.
  • #1
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help me to find this one!
the weight of the door is 110N. what is the moment experience by each hinges?the diagram can be seen in the attachment file!
 
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  • #2
You need to work out the distance from the centre of gravity of the door, to the hinge itself.
From there, just apply the usual formula. M= Fd
 
  • #3
i thought it is M=F.perpendicular distance! and the angle of the hinges to the centre of gravity is not 90 degree? or i am wrong probably. but can you show me the solution to the question.anyone?any way is there any attachment on post 1?
 
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  • #4
Yeah, the moment is the force x perpendicular distance to line of action of the force. There's no attachment.
 
  • #5
ok, try this one!
 
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  • #6
Can't open it. I get a "invalid or corrupted" message.

Assuming the door (so the center of gravity is on the center line) is uniform and that there are two hinges, multiply half the weight of the door by the horizontal distance from each hinge to the center line of the door.
 
  • #7
i don't think i can upload the diagram. but i will describe it. it is the hinges of a door with weight of 110N. First the height of the door is 1.9 m and the width is 1 m. the first hinges (located on the edge as normal doors), is 0.1 m and the second is 1.7 m from the origin. hence state the moment experienced by each hinges? will both hinges experienced the same force although of different position in symmetrical to the centre of gravity?
 
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  • #8
adiputra said:
i don't think i can upload the diagram. but i will describe it. it is the hinges of a door with weight of 110N. First the height of the door is 1.9 m and the width is 1 m. the first hinges (located on the edge as normal doors), is 0.1 m and the second is 1.7 m from the origin. hence state the moment experienced by each hinges? will both hinges experienced the same force although of different position in symmetrical to the centre of gravity?

The meaning of "moment experienced by each hinge" needs to be understood. The bottom line is that if all forces acting on each hinge are considered, and the door is hanging there without moving, the total moment calculated about each hinge is zero. If it were otherwise, the door would be twisting the hinges off the frame.

The answer to the problem as stated is zero. The net moment calculated about any point in any statics problem is zero. The more interesting question is to find the forces provided by each hinge required to make those moments zero.

In the ideal case, the hinges would be mounted so that half of the weight of the door is supported by each hinge. It takes an incredibly talented carpenter to even come close to that condition. If either hinge is attached to the frame slightly higher than the other, it will bear all of the weight; the other hinge will only serve to provide a force parallel to the floor, and thus provide a moment about the other hinge. Fortunately, as long as one hinge is directly above the other hinge it does not matter which hinge is bearing most or all of the weight. The vertical forces provided by the hinges act along the line through those hinges and do not contribute to the moments acting about those hinges.

Each hinge can be considered as the center of moments. In both cases the weight of the door can be taken as being located at its center of mass. The moment from this force is the weight of the door times the perpendicular distance between the line of the force (straight down) and the location of the hinge. It is the same for either hinge. For moments about the lower hinge, the weight moment must be counteracted by the moment from the top hinge. The top hinge will provide a horizontal force toward the frame, and the perpendicular distance between the line of that force and the lower hinge is the distance between hinges. Similarly, the weight of the door and the horizontal force from the lower hinge, away from the frame, provide counteracting moments about the upper hinge.
 

1. What is moment experience?

Moment experience is the measure of rotational force, also known as torque, that is applied to an object around a fixed point.

2. How is moment experience calculated?

Moment experience is calculated by multiplying the force applied to an object by the distance from the point of rotation to the line of action of the force.

3. What is the unit of measurement for moment experience?

The unit of measurement for moment experience is Newton-meters (Nm) in the metric system and foot-pounds (ft-lb) in the Imperial system.

4. How does the moment experience differ for each hinge?

The moment experience differs for each hinge depending on the distance from the point of rotation to the line of action of the force applied and the magnitude of the force.

5. Why is moment experience important in engineering and physics?

Moment experience is important in engineering and physics because it helps determine the stability and strength of structures and machines. It is also crucial in understanding the behavior of objects in motion and the principles of equilibrium.

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