Modiolus. the central core of bone within the cochlea. It forms the axis of the cochlear spiral, which coils for 2.75 turns.

Vision is the least developed sense at birth as the womb is a dark place and there is little opportunity for development. Vision, like hearing, does develop rapidly over the early years of a baby’s life.

The Special Senses

static equilibrium – The special sense which interprets the position of the head permitting the CNS to maintain stability and posture when the head and body are not moving; it is detected by mechanoreceptors in the vestibule of the inner ear, the utricle and saccule, which each contain a macula with the receptors for …

Static Equilibrium

1. Identify the object to be analyzed.
2. Set up a free-body diagram for the object.
3. Set up the equations of equilibrium for the object.
4. Simplify and solve the system of equations for equilibrium to obtain unknown quantities.
5. Evaluate the expressions for the unknown quantities that you obtained in your solution.

Receptors for two sensory modalities (hearing and equilibrium) are housed in the ear. The external ear, the middle ear, and the cochlea of the inner ear are involved with hearing. The semicircular canals, the utricle, and the saccule of the inner ear are involved with equilibrium.

The inner ear contains parts (the nonauditory labyrinth or vestibular organ) that are sensitive to acceleration in space, rotation, and orientation in the gravitational field.

The body contains a lot of dynamic equilibrium because it means the body is in a state of balance with movement. The body experiences an acid-base reaction that needs to be kept at balance so that the body can be kept at a favorable pH level.

In your body, glucose is in dynamic equilibrium. While glucose has periods of high and low concentration, it is relatively stable. If glucose levels in your body fall out of dynamic equilibrium, or you cannot replace the glucose you use, you would eventually die.

The process of equilibrium governs many of the chemical reactions taking place in the human body. Enzymes work this way. An enzyme is a very, very large molecule in the body that works as a catalyst – it lowers the energy barrier of a reaction so that it can proceed at a faster rate.

For an object to be in equilibrium, it must be experiencing no acceleration. This means that both the net force and the net torque on the object must be zero.

There are three types of equilibrium: stable, unstable, and neutral. Figures throughout this module illustrate various examples.

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.

A two-force member is a structure that has exactly two points where external forces can be applied. This means that the net force acting at those two points must lie along the line that contains those two points of application.

For an object to remain in equilibrium, two conditions must be satisfied – both the net force and the net torque must be equal to zero. An example of an object in equilibrium is a rod that is free to rotate about a hinge at one end.

A two force member is a body that has forces (and only forces, no moments) acting on it in only two locations.

What are the three elements of force? What is power? The size, direction and point of action of the force are collectively referred to as the “three elements of force.”Line segments are often used to indicate force.

Types of Forces

If a joint has only two non-collinear members and there is no external load or support reaction at that joint, then those two members are zero- force members. In this example members DE, DC, AF, and AB are zero force members.

In the field of engineering mechanics, a zero force member is a member (a single truss segment) in a truss which, given a specific load, is at rest: neither in tension, nor in compression. If three members meet in an unloaded joint of which two are collinear, then the third member is a zero-force member.

When a member force points toward the joint it is attached to, the member is in compression. If that force points away from the joint it is attached to, the member is in tension.

The direction of tension is the pull which is given the name tension. Thus, the tension will point away from the mass in the direction of the string/rope. In case of the hanging mass, the string pulls it upwards, so the string/rope exerts an upper force on the mass and the tension will be in the upper side.

Tension is positive (pulling apart) and compression is negative (pushing together). Shear Stress: For shear stresses, there are two subscripts.