How does mass affect inertia

When applying the same force on both objects, will they always behave the same? My intuition tells me the moment of inertia will only depend on center of mass rather than mass distribution, am I right? Moment of Inertia depends on both the mass and the distribution of the mass. Further away from the axis of rotation, a unit of mass will cause a greater moment of inertia. Therefore, if you have two bodies of the same mass, same centre of mass, but a different distribution; they can have very different moments of inertia.

Consider the difference between a circular plate with even mass distribution, and a circular plate with mass concentrated at the edges. To simplify, you can consider the objects as a sum of point masses and their moments of inertia. Your intuition is incorrect. The solid sphere will be going faster than the hollow sphere at the bottom of the ramp, and will reach the bottom of the ramp in less time than it takes the hollow sphere to reach the bottom.

There are two parts to the motion of a rigid body. The motion of the center of mass point and the rotation about the center of mass.

But to describe the rotation you need the mass moment of inertia and the location of the forces. The mass moment of inertia depends on the distribution of mass. In 2D. That is, an object in space resists changes in its state of motion.

A force must be applied to set a stationary object in motion. Newton's laws rule - everywhere! Fred spends most Sunday afternoons at rest on the sofa, watching pro football games and consuming large quantities of food. What affect if any does this practice have upon his inertia?

Fred will increase his mass if he makes a habit of this. And if his mass increases, then his inertia increases. Ben Tooclose is being chased through the woods by a bull moose that he was attempting to photograph. The enormous mass of the bull moose is extremely intimidating. Yet, if Ben makes a zigzag pattern through the woods, he will be able to use the large mass of the moose to his own advantage.

Explain this in terms of inertia and Newton's first law of motion. The large mass of the bull moose means that the bull moose has a large inertia. Thus, Ben can more easily change his own state of motion make quick changes in direction while the moose has extreme difficulty changing its state of motion.

Physics for better living! Two bricks are resting on edge of the lab table. Shirley Sheshort stands on her toes and spots the two bricks. She acquires an intense desire to know which of the two bricks are most massive.

Since Shirley is vertically challenged, she is unable to reach high enough and lift the bricks; she can however reach high enough to give the bricks a push. Discuss how the process of pushing the bricks will allow Shirley to determine which of the two bricks is most massive. What difference will Shirley observe and how can this observation lead to the necessary conclusion? The bricks, like any object, possess inertia. That is, the bricks will resist changes in their state of motion.

If Shirley gives them a push, then the bricks will offer resistance to this push. The one with the most mass will be the one with the most inertia. This will be the brick which offers the most resistance.

This very method of detecting the mass of an object can be used on Earth as well as in locations where gravitational forces are negligible for bricks. Physics Tutorial. My Cart Subscription Selection. Student Extras. Unbalanced Forces. Watch It! Another thought experiment of Galileo's is explained in this video using an actual experiment performed with modern-day equipment.

A physics instructor explains the property of inertia using a phun physics demonstration. See Answer According to Newton's first law, the rock will continue in motion in the same direction at constant speed. A sphere is moving around in the air. If the moment of inertia is 10 Kg m2 and a radius of 1m What is the moment of inertia of a ball of a mass of 5 Kg and radius of 3 cm?

Why is the moment of inertia important? How can I calculate the moment of inertia of a wheel? How is moment of inertia measured? How does the radius affect the moment of inertia?