# What is Hinges: Definition and 24 Discussions

A hinge is a mechanical bearing that connects two solid objects, typically allowing only a limited angle of rotation between them. Two objects connected by an ideal hinge rotate relative to each other about a fixed axis of rotation: all other translations or rotations being prevented, and thus a hinge has one degree of freedom. Hinges may be made of flexible material or of moving components. In biology, many joints function as hinges like the elbow joint.

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1. ### Determining Acceleration of Hinge in a Beam and Hinge Structure

Homework Statement The following structure,A force F is applied to the right hinge.If the mass of the rods are equal ,and the length of the rod is equal,the intial angle is also equal to 90 degrees (a square),What is the intial acceleration of leftmost hinge ? Homework Equations Coordinate...
2. ### MHB Election Outcome Hinges on Vote Ratios: Can You Solve It?

In a recent election, the ratio of the number of voters for the Purple Party to the number of voters for the Pink Party was 15:16 and the Pink Party won the election. Had 300 more people voted for the Purple Party and 200 fewer people voted for the Pink Party, the ratio would have been 11:10 and...
3. ### Linearly-damped rotational motion

http://imgur.com/a/8QjoW http://imgur.com/a/8QjoW Hello- I am trying to determine the dynamics of this linearly-damped hinge. Assuming that: v(0) = 0 damping constant = b door has mass = m I was able to determine that: ∑Fx = -Fd * cos(45-θ/2) + Rx = m*dvx/dt ΣFy = -Fd * sin(45-θ/2) - Fg +...
4. ### Determine forces in beam with hinges

Homework Statement Is it possible to find the VA , VB and VC without ' breaking ' the beam into 2 parts ? Homework EquationsThe Attempt at a Solution Here's my working , i gt Moment about A = 10(1) -VB(2) -VC(4) +5(3)(4 + (3/2) ) = 0 Hence , 92.5-2VB -4VC= 0 moment about B = VA(2) -10-VC(2)...
5. ### Solve Acceleration of Hinges Problem on Brilliant.org

This is a problem posted by a member on Brilliant.org (https://brilliant.org/problems/acceleration-of-hinges/). I found one way to solve the problem, but it is really long, and i am looking for some different solutions. The problem is- Four similar rods of uniform density are connected with...
6. ### Insights Atomic positioning with DNA hinges - Comments

klotza submitted a new PF Insights post Atomic Positioning with DNA Hinges Continue reading the Original PF Insights Post.
7. ### Unsure of mechanics problem, circular door on hinge...

1. In the attached imjage, the centre of gravity of an open door acts at G equal to 255N; a) Determine the x,y,z, components of reaction at the hinge A in equilibrium b) Determine the force along CB Little stuck with this problem, obviously this falls under resolving forces. I assumed Az,Ay = 0...
8. ### Solving Beam with 2 Hinges: Struggling with FBD & Forces

Hi all, Having trouble with the following question, trying to work out the FBD and forces. I am fine with working out the max tensile and compressive forces however I can't get that far as the two hinges are throwing me off. As I understand, the moment at the hinges should be 0, is this...
9. ### Statics: find torque at door hinges

Homework Statement Door weighs 20kg, and is held open by force P at doorknob opposing 15kg weight attached at C and wrapped around pulley. Theta is 90 degrees, so door is on x axis. Find torques on hinges A & B[/B]Homework Equations P is 118.8N in -k direction, which agrees with answer in...
10. ### Fluid Mechanics: Hydrostatic Pressure on a gate with hinges

Homework Statement Homework Equations Fluid Mechanics The Attempt at a Solution Lets start with the easy part: The pressure of the air is constant so the pressure will act as if it's a concentrated force on the center of gravity of the gate. F = PA = (10,000Pa)(.3)(.6)=1800N The moment...
11. ### Calculating Torques on a Door with Hinges

Homework Statement Consider a do or, hanging on two hinges (s ee figure). The do or is L tall and d wide, and the hinges are placed at heights L/4 (point A) and 3 L/4 (point B) from the floor. The door is uniform, and so its centre of mass is in the middle of the door (point C) b) What is the...
12. ### Spring hinges on door what is the ideal angular velocity exerted

Can someone tell me what is the best angular velocity to be exerted on the door for it to close automatically if I were to design a door with spring hinges.
13. ### Moment of inertia for door hinges

How do we find out that the moment of inertia about the hinges of a door with a width w is I=M w2/3. I find it like this in a book and also in table for the moments of inertia of homogeneous rigid objects with different geometries (about a long thin rod with rotation axis trough end). Thank you.
14. ### Horizontal Forces exerted by door hinges

Homework Statement A door of width 1.00 m and height 2.30 m weighs 272 N and is supported by two hinges, one 0.40 m from the top and the other 0.40 m from the bottom. Each hinge supports half the total weight of the door. Homework Equations Torque = rFsin(theta) The Attempt at a Solution I...
15. ### Weight of a 1.02m x 2.05m Door Supported by Two Hinges

A door of width 1.02 m and height 2.05 m weighs 289 N and is supported by two hinges, one 0.600 m from the top and the other 0.600 m from the bottom. Each hinge supports half the total weight of the door. Assuming that the door's center of gravity is at its center, find the horizontal...
16. ### What is the rotational inertia of the door about the hinges?

Thank you all for taking the time to help me out. Here's what I'm given: Homework Statement A solid door of mass M = 19 kg and width = 128 cm is hit at a right angle by a mud ball of mass m = 0.6 kg, which, as Fig. 10–44 shows, hits the door at the edge with speed v = 16 m/s and sticks...
17. ### Vertical forces on door hinges

Homework Statement A door with weight Mg has a horizontal width W and a vertical length L. There are two hinges that hold up the door along the right side of the door. The top hinge is a distance d from the top of the door and the bottom hinge is a distance d from the bottom of the door...
18. ### Forces on Hinges HW Statement: F&Tau Calculation

Homework Statement A door 2.30 m high and 1.30m wide, has a mass of 13.0 kg. A hinge 0.40 m from the top and another hinge 0.40 m from the bottom each support half the door's weight. Assume that the center of gravity is at the geometrical center of the door, and determine the horizontal and...
19. ### Calculating Torque of Hinges on a Door with Multiple Forces

A door 2.30m high and 1.30m wide,has a mass of 13.0kg. A hinge 0.40m from the top and another hinge from the bottom each support half the door`s weight. By assumming that the center of gravity is at the geometrical center of the door,determine the horizontal and vertical force components exerted...
20. ### Door naturally swings if the hinges are not properly aligned

I like it if someone could show me why a door naturally swings if the hinges are not properly aligned. I am not sure, but it might have been when a door is hanging on only one hinge that it naturally swings. Thank you.
21. ### What is the moment experience by each hinges?

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!
22. ### Calculating Force on a Table Attached to Hinges

A 100 Newton table surface (table without the legs) is attached to hinges in a wall. a chair hold the table surface in a horizontal position . The chain (chain forms a hypoteneus with the table surface and the wall) is attached to position in the table surface 0.25m from the end of the table...
23. ### How Do Torque and Hinge Placement Affect a Door's Stability?

I'm having quite a bit of trouble with this problem. It seems easy, but I just can't seem to get the idea. I'm able to calculate the vertical components of the forces by using the summation of forces in the y direction equal to zero. The horizantal components, I'm pretty sure I need to use...
24. ### Force on door from two hinges - easy - help anyone?

torque/force problem - two door hinges - help anyone? A large door of height - 2.1 m - along y-axis that extends vertically upward and width - 0.95 m - along x-axis that extends outward from the hinged edge of the door. A hinge at 0.30 m from the top and a hinge at 0.30 m from the bottom, each...