What structures contribute to an individual's static equilibrium? The horizontally positioned utricle The utricle and saccule are the two otolith organs in the vertebrate inner ear. They are part of the balancing system in the vestibule of the bony labyrinth. They use small stones and a viscous fluid to stimulate hair cells to detect motion and orientation. The utricle detects linear accelerations and head-tilts in the horizontal plane. The word utricle comes from Latin uter, meaning 'leather bag'.Utricle
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What happens when a structure is in static equilibrium?
A structure is in static equilibrium when there is no net force or moment on it. If a structure that is initially stationary has a net force, it will start to move and will no longer be in equilibrium. If a structure that is initially stationary has a net moment (or torque ), then it will start to rotate.
What are the principles of statics?
Principles of statics consists of the study of structures that are at rest under static equilibrium conditions. To ensure equilibrium, net torque acting on the structure should be zero.
Which component parts of the structural system are in equilibrium?
For this situation, all component parts of the structural system are also in equilibrium. A structure is in equilibrium with a system of applied loads when the resultant force in any direction and the resultant moment about any point are zero.
What are the principles of static analysis in structural engineering?
Principles of statics consists of the study of structures that are at rest under static equilibrium conditions. To ensure equilibrium, net torque acting on the structure should be zero. The static analysis methods provide the means to analyze and determine both internal and external forces acting on a structure.
What structures contribute to an individual's static equilibrium?
The ear maintains our sense of balance through two sets of structures: the utricle and saccule, and the semicircular canal. They help maintain static equilibrium and dynamic equilibrium, respectively.
What is the structure of static equilibrium?
What is static equilibrium? Technically, a body (or structure) is in static equilibrium if it is not accelerating. This means that it is moving at a constant velocity.
What enables static equilibrium?
The vestibular system is the sensory apparatus of the inner ear that helps the body maintain its postural equilibrium. The information furnished by the vestibular system is also essential for coordinating the position of the head and the movement of the eyes.
What are some examples of static equilibrium?
(iv) a ball kept on the ground. Hence, any non-moving stationary object can be considered to be in static equilibrium. Note: In some cases, like when equal and opposite forces are applied on a stationary rod kept on a table, the net force on the rod becomes equal to zero but it gains some torque in the process.
What is static equilibrium quizlet?
Static equilibrium. An analysis of the forces and torques on a system at rest or at a constant velocity.
What does static equilibrium meaning?
: equilibrium of a system whose parts are relatively at rest (such as a steel truss resting on piers)
Which part of ear is responsible for static balance?
Static balance - utriculus and sacculus (vestibule)
What part of the ear is responsible for static equilibrium?
The vestibuleThe vestibule lies between the semicircular canals and the cochlea (eardrum). The vestibule is responsible for maintaining static equilibrium while the semicircular canals maintain dynamic equilibrium.
Which structure is important to your sense of balance and equilibrium?
The ear is a sensory organ that picks up sound waves, allowing us to hear. It is also essential to our sense of balance: the organ of balance (the vestibular system) is found inside the inner ear. It is made up of three semicircular canals and two otolith organs, known as the utricle and the saccule.
Which of the following is an example of static equilibrium quizlet?
An example of static equilibrium occurs when nodding one's head "yes."
What contains the sensory receptors for static equilibrium?
The vestibule is the primary detector of changes in static equilibrium. A sensory receptor called a macula is located in the walls of the saccule and utricle, the two bulblike sacs of the vestibule.
When is a structure in static equilibrium?
A structure is in static equilibrium when there is no net force or moment on it. If a structure that is initially stationary has a net force, it will start to move and will no longer be in equilibrium. If a structure that is initially stationary has a net moment (or torque ), then it will start to rotate. To avoid these situations, all of the ...
What does it mean when a structure is not in equilibrium?
If a structure is not in equilibrium, that means it is accelerating, which is rarely a good situation. Accelerations on structures are encountered in the design of structures for dynamic loadings such as wind or earthquake loads; however, such situations are beyond the scope of this book.
How to find moment equilibrium?
To find the moment caused by a force on a rigid body, you need to define a reference point on the body. Any reference point is okay (any point on the body), as long as the same reference point is used to calculate all of the moments. To calculate the moment caused by a force, the force is multiplied by the moment arm or eccentricity which is equal to the perpendicular distance between the force and the reference point. That is, it is the distance between the force vector (the arrow) and a line that is parallel to the force vector and also runs through the reference point. It is also important to consider the direction of the moment caused by the force relative to the reference point. Generally, one rotation direction is considered positive and the other is considered negative. In this text, counter clock-wise (CCW~ ↶) rotations will be considered positive and clock-wise rotations (CW~ ↷) will be considered negative.
Why are Mz2 and F1E1 positive?
The moments Mz2, F1e1 and F2e2 are all positive because they both would all cause a counter clock-wise (CCW~ ↶) rotation of the rigid body around the reference point (if it was not in equilibrium). Likewise, Mz1 is negative because it would cause a clock-wise (CW ↷) rotation.
Does F3e3 have a positive moment?
Of course, the magnitudes of the moment arms e1 and e2 have also changed. In addition, there is an additional term in the moment equilibrium because F3 is no longer concurrent with the reference point and so , therefore, produces a positive (CCW ↶) moment of F3e3.
Does the equilibrium change if you use the reference point location?
Whether you use the reference point location shown on the left or right side of the Figure 1.2, the equilibrium will not change.
When solving static equilibrium problems, are we free to choose the pivot location?
This example shows that when solving static equilibrium problems, we are free to choose the pivot location. For different choices of the pivot point we have different sets of equilibrium conditions to solve. However, all choices lead to the same solution to the problem.
What are the conditions of equilibrium?
Conditions for equilibrium require that the sum of all external forces acting on the body is zero (first condition of equilibrium), and the sum of all external torques from external forces is zero (second condition of equilibrium). These two conditions must be simultaneously satisfied in equilibrium. If one of them is not satisfied, the body is not ...
What is torque on the body caused by?
torque on the body caused by its weight; it occurs when the center of gravity of the body is not located on the axis of rotation. second equilibrium condition. expresses rotational equilibrium; all torques due to external forces acting on the body balance out and their vector sum is zero. static equilibrium.
What is the second equilibrium condition?
The second equilibrium condition means that in equilibrium, there is no net external torque to cause rotation about any axis. The first and second equilibrium conditions are stated in a particular reference frame. The first condition involves only forces and is therefore independent of the origin of the reference frame.
When is a rigid body in equilibrium?
We say that a rigid body is in equilibrium when both its linear and angular acceleration are zero relative to an inertial frame of reference. This means that a body in equilibrium can be moving, but if so, its linear and angular velocities must be constant.
Is there a distinction between static equilibrium and equilibrium?
Since the laws of physics are identical for all inertial reference frames, in an inertial frame of reference, there is no distinction between static equilibrium and equilibrium. According to Newton’s second law of motion, the linear acceleration of a rigid body is caused by a net force acting on it, or. ∑k →F k = m→a CM. ∑ k F → k = m a → CM.
How to solve static equilibrium?
By the end of this section, you will be able to: 1 Identify the physical conditions of static equilibrium. 2 Draw a free-body diagram for a rigid body acted on by forces. 3 Explain how the conditions for equilibrium allow us to solve statics problems.
When solving static equilibrium problems, are we free to choose the pivot location?
This example shows that when solving static equilibrium problems, we are free to choose the pivot location. For different choices of the pivot point we have different sets of equilibrium conditions to solve. However, all choices lead to the same solution to the problem.
What is torque on the body caused by?
torque on the body caused by its weight; it occurs when the center of gravity of the body is not located on the axis of rotation. second equilibrium condition. expresses rotational equilibrium; all torques due to external forces acting on the body balance out and their vector sum is zero. static equilibrium.
What is the second equilibrium condition?
The second equilibrium condition means that in equilibrium, there is no net external torque to cause rotation about any axis. The first and second equilibrium conditions are stated in a particular reference frame. The first condition involves only forces and is therefore independent of the origin of the reference frame.
When is a rigid body in equilibrium?
We say that a rigid body is in equilibrium when both its linear and angular acceleration are zero relative to an inertial frame of reference. This means that a body in equilibrium can be moving, but if so, its linear and angular velocities must be constant.
What are the conditions of equilibrium?
Conditions for equilibrium require that the sum of all external forces acting on the body is zero (first condition of equilibrium), and the sum of all external torques from external forces is zero (second condition of equilibrium). These two conditions must be simultaneously satisfied in equilibrium.
Is the state of rest and uniform motion artificial?
Notice that the distinction between the state of rest and a state of uniform motion is artificial—that is, an object may be at rest in our selected frame of reference, yet to an observer moving at constant velocity relative to our frame, the same object appears to be in uniform motion with constant velocity.
When is a structural system in equilibrium?
A structure is in equilibrium with a system of applied loads when the resultant force in any direction and the resultant moment about any point are zero.
What are the principles of statics?
Principles of statics. Principles of statics consists of the study of structures that are at rest under static equilibrium conditions. To ensure equilibrium, the forces acting on a structure must balance, net torque acting on the structure should be zero. The static analysis methods provide the means to analyze and determine both internal ...
What is statically determinate structure?
A statically determinate structure is one in which all the unknown member forces and external reactions may be determined by applying the equations of equilibrium. An indeterminate or redundant structure is one that possesses more unknown member forces or reactions than the available equations of equilibrium.
What are the conditions of equilibrium?
Conditions of equilibrium. In order to apply the principles of statics to a structural system, the structure must be at rest. This is achieved when the sum of the applied loads and support reactions is zero and there is no resultant couple at any point in the structure.
What is static analysis?
The static analysis methods provide the means to analyze and determine both internal and external forces acting on a structure. For structures in a plane, three equations of equilibrium are used for the determination of external and. internal forces.
Which system is responsible for the central processing of vestibular information?
Central Processing of Vestibular Information. Balance is coordinated through the vestibular system, the nerves of which are composed of axons from the vestibular ganglion that carries information from the utricle, saccule, and semicircular canals.
Why does the otolithic membrane move?
The otolithic membrane moves separately from the macula in response to head movements. Tilting the head causes the otolithic membrane to slide over the macula in the direction of gravity. The moving otolithic membrane, in turn, bends the sterocilia, causing some hair cells to depolarize as others hyperpolarize.
Where does the hair cell attach to the ampulla?
The stereocilia of these hair cells extend into the cupula, a membrane that attaches to the top of the ampulla. As the head rotates in a plane parallel to the semicircular canal, the fluid lags, deflecting the cupula in the direction opposite to the head movement.
How many canals can give a very precise indication of head movement in three dimensions?
The movement of two canals within a plane results in information about the direction in which the head is moving, and activation of all six canals can give a very precise indication of head movement in three dimensions.
Which canals are oriented horizontally and vertically?
The semicircular canals contain several ampullae, with some oriented horizontally and others oriented vertically. By comparing the relative movements of both the horizontal and vertical ampullae, the vestibular system can detect the direction of most head movements within three-dimensional (3-D) space.
Which axons are the second target of the axons of neurons in the vestibular
A second target of the axons of neurons in the vestibular nuclei is the spinal cord , which initiates the spinal reflexes involved with posture and balance.
What is engineering statics?
Engineering statics is the study of rigid bodies in equilibrium so it’s appropriate to begin by defining what we mean by rigid bodies and what we mean by equilibrium. A body is an object, possibly made up of many parts, which may be examined as a unit.
What happens if all the forces acting on a body sum to zero?
Reading it from left to right it says that if all the forces acting on a body sum to zero, then the body will be in equilibrium. If you read it from right to left it says that if a body is in equilibrium, then all the forces acting on the body must sum to zero.
Is a rigid body assumption an idealization?
You will drop the rigid body assumption and study deformation, stress, and strain in a later course called Strength of Materials or Mechanics of Materials.
Is a body in equilibrium accelerating?
A body in equilibrium is not accelerating. As you learned in physics, acceleration is the rate of change of velocity, and is a vector quantity. For linear motion, . a = d v d t. 🔗. For an object in equilibrium a = 0 which implies that the body is either stationary or moving with a constant velocity. . a = 0 ⟹ { v = 0 v = C.
What Is Static Equilibrium?
How Can You Tell When A Structure Is in Equilibrium?
- A structure is in static equilibrium when there is no net force or moment on it. If a structure that is initially stationary has a net force, it will start to move and will no longer be in equilibrium. If a structure that is initially stationary has a net moment (or torque), then it will start to rotate. To avoid these situations, all of the forces in every direction must counterbalance each other. The s…
Solving For Unknown Forces and/or Moments Using Equilibrium
- Knowing the equations of static equilibrium and , if all the forces are known it is a simple matter to check and see if a body is in equilibrium or not by simply applying those equations and seeing if they are satisfied (i.e. the forces and moments add up to zero in each direction). This ability, in itself, is not terribly useful for structural analysis. Unless we are studying a system that is subjec…