Inertia is the property of an object that resists changes in its state of motion. It is directly related to the mass of the object. The greater the mass, the greater the inertia. This means that heavier objects require more force to change their motion compared to lighter objects.
For example, consider a small car and a large truck. If both are at rest and you want to move them, you will find it much easier to push the small car than the large truck. The truck, having more mass, possesses more inertia, making it harder to get it moving. Similarly, once the truck is in motion, it will also be harder to stop due to its larger inertia.
This relationship is fundamental to Newton’s first law of motion, which states that an object at rest will stay at rest, and an object in motion will stay in motion unless acted upon by a net external force. Therefore, mass plays a crucial role in determining an object’s inertia, impacting how it responds to applied forces.