The moment of inertia of a system of particles is given by, I = ∑ m i r i 2 [from equation (1)] where r i is the perpendicular distance from the axis to the ith particle which has mass m i. In other words, it is the tendency of an object to continue moving in a straight line at the same speed until friction or some other object slows it down or makes the object change direction. A leaf falling from the branch of a tree that is disturbed by a strong wind is an example of inertia of rest. Although it is a simple matter to determine the moment of inertia of each rectangular section that makes up the beam, they will not reference the same axis, thus cannot be added. It is always considered with respect to a reference axis such as X-X or Y-Y. that’s inertia. Determine the moment of inertia of the cross section about the x axis. Inertia is classified into three types: inertia of rest, inertia of motion and inertia of direction. In physics, when you calculate an object’s moment of inertia, you need to consider not only the mass of the object but also how the mass is distributed. Do you think the moment of inertia of this rod that's the same mass and length that it was, we're just rotating it about the center, do you think this moment of inertia is gonna be bigger than, smaller than or equal to what the moment of inertia was for a rod rotated about the end. A person that falls down after carelessly jumping off a moving train is an example of inertia of motion. This is because it is the resistance to the rotation that the gravity causes. We can measure the moment of inertia by using a simple pendulum. Learn moment of inertia formula here. Whenever a car suddenly decelerates(stops) you know how you feel a force pushing and pulling on you? Inertia Examples. Example: Moment of Inertia of Rigid Bodies. The moment of inertia of continuous mass distribution is found by using the integration technique. Calculation Example – Torsional moment-Stress. The moment of inertia, otherwise known as the angular mass or rotational inertia, of a rigid body, is a quantity that determines the torque needed for a desired angular acceleration about a rotational axis; similar to how mass determines the force needed for the desired acceleration. It is a mathematical property of a section concerned with a surface area and how The moment of inertia (second moment or area) is used in beam theory to describe the rigidity of a beam against flexure (see beam bending theory). Moment of inertia and Its calculation. Thus, the moment of inertia of a rigid composite system is the total sum of the moments of inertia of its component subsystems. Calculation Example – Reinforced Concrete Column at Stress. However, if we found the moment of inertia of each section about some For example, if two disks have the same mass but one has all the mass around the rim and the other is solid, then the disks would have different moments of inertia. Inertia is an object's ability to resist changes in motion. Moment of Inertia 5 An example of this is the concrete T-beam shown.

Moment of Inertia and Properties of Plane Areas The Moment of Inertia (I) is a term used to describe the capacity of a cross-section to resist bending. Calculation Example - Calculate the Axial Forces of the Truss Members. The figure shows the cross section of a beam made by gluing four planks together. We already know that the moment of inertia of a system about axis of rotation is given as where m i is the mass of the ith particle and r i is its perpendicular distance from the axis of rotation; For a system consisting of collection of discrete particles ,above equation can be used directly for calculating the moment of inertia Calculation Example – Calculate tension force using virtual work.
10.2 Method of Composite Areas Example 2, page 1 of 2 2. Calculation Example – Calculate shear stress for temperature load. Inertia. Example Simple Pendulum.