Inertia and Conservation

Physics has two interesting topics, namely inertia and angular momentum. Inertia can be defined as the resistance an object or any physical body offers to oppose any change in its velocity. On the other hand, angular momentum, also referred to as rotational momentum, is defined as the product of the position vector and the momentum vector. The position vector of any quantities is denoted by r and the momentum vector of any quantity is denoted by p. It brings out the angular momentum formula as r × p. This article aims at giving you a comprehensive piece of knowledge on inertia and angular momentum with detailed information on the dimension of angular momentum.

Introduction to Inertia

Inertia pertains to the resistance offered by any physical body as an opposition to a change in its velocity. This change in velocity can be a change in the body’s speed or a change in the direction of its motion. In both cases, inertia is the tendency of any physical body to maintain its motion in a constant speed and straight line without any external force. When it comes to the definition of inertia, it is stated that inertia is a resistance power in everybody to preserve its present state. 

Different Types of Inertia 

In general, there are three types of inertia, namely

Inertia of Rest

The inertia of rest can be defined as the resistive force applied to any physical object to maintain the state of rest until an external force is applied to it. 

Inertia of Direction

The inertia of direction can be defined as the resistive force applied to any physical object to maintain the direction of motion until an external force is applied.

Inertia of Motion

The inertia of motion can be defined as a resistive force applied to any physical object to maintain the state of motion until an external force is applied to it.

Gallelio’s Explanation of Inertia

The great scientist Galileo explained the phenomenon of inertia with an experiment in which he used two different inclined planes and a ball. He showed that when the ball rolls down on the first plane, it climbs up on the other plane. The inertia was supported by the distance that the ball covered on the other plane when rolled down from the first plane. It covers the same distance on the second plane as it was rolled down. Now Galileo changed the slope of the second ramp and again rolled down the ball.

The result was still the same: the ball travelled the same distance. Again Galileo changed the slope of the second ramp, and this time, it was decreased to zero. Theoretically, if we ignore the force of friction, the ball will travel an infinite distance with constant velocity. Still, in this case, the ball comes to rest after travelling a certain distance. With this experiment, Galileo concluded that the statement of Aristotle was wrong and it was a wrong assumption that we need a force to keep a body in uniform motion.

Introduction to Angular Momentum 

In physics, two types of angular momentum are associated with an object, namely the spin angular momentum and the orbital angular momentum. The spin angular momentum refers to the angular momentum associated with the body’s centre of mass, whereas the orbital angular momentum is associated with a centre of rotation. The angular momentum depends on both rotational inertia and rotational velocity. In simple words, then our body experiences a change in its shape, and the angular velocity also experiences the change provided that there is no requirement for external torque. To understand the above-given statement, let’s take an example of an ice skater. When the ice skater starts spinning, they experience a rotation velocity change and to control it, they pull their arms outwards or hold them inwards.

Angular Momentum Formula

The angular momentum formula is given below:

L= m×v×r

Where,

L stands for angular momentum

m refers to the mass of the body

v stands for body’s velocity

r refers to the radius

Dimension of Angular Momentum

The dimension of Angular momentum or the dimensional formula of angular momentum is M¹L²T-¹.

Conclusion 

The concept of inertia is an important topic in fundamental physics. Inertia pertains to the opposing force produced by anybody to resist a sudden change in the speed direction or the state of the body. The concept of inertia is also explained by the second law of Newton, which states that a body remains in a state of rest or motion until and unless it experiences any external force. In this article, we discussed inertia and angular momentum with a detailed look at the formula and the concept of angular momentum to provide you with comprehensive knowledge on these topics.