# What's the difference between Inertia and Impulse?

Because the definitions sound really similar.

## Inertia and impulse are related concepts in physics, but they have distinct meanings and implications.

Inertia refers to the resistance an object has to changes in its state of motion. It is commonly associated with Isaac Newton's first law of motion, also known as the law of inertia, which states that an object at rest tends to stay at rest, and an object in motion tends to stay in motion with the same speed and direction, unless acted upon by an external force.

To understand inertia, you need to consider the mass of an object. The more massive an object is, the greater its inertia and resistance to changes in motion. For example, it requires more force to move a heavy boulder than to move a small pebble because the boulder has greater inertia.

Impulse, on the other hand, refers to the change in momentum that occurs when a force acts on an object for a certain amount of time. Momentum, symbolized by the letter "p," is the product of an object's mass and its velocity. Mathematically, impulse is equal to the force applied to an object multiplied by the time interval over which the force is exerted.

To calculate impulse, you need to know both the force applied to an object and the time over which the force acts. The equation for impulse is commonly expressed as:

Impulse = Force * Time

Impulse can cause a change in an object's momentum, which is a measure of its motion. When a force is applied to an object, its momentum can increase or decrease depending on the direction and magnitude of the force applied.

In summary, inertia refers to an object's resistance to changes in motion, while impulse refers to the change in momentum caused by a force acting on an object. Inertia is related to an object's mass, while impulse depends on the force and time over which it acts.