Which of the following statements best describes inertia?
Inertia depends on the size of an object.
Inertia is proportional to speed.
Inertia is a vector quantity.
Inertia is a resistance to change in motion.
The correct answer and explanation is :
The correct statement that best describes inertia is:
Inertia is a resistance to change in motion.
Explanation:
Inertia is a fundamental concept in physics, especially within Newtonian mechanics. It refers to an object’s tendency to resist changes in its state of motion. In other words, an object will keep moving at a constant velocity in a straight line or remain at rest unless acted upon by an external force. This principle is encapsulated in Newton’s First Law of Motion, which states that “an object in motion will remain in motion, and an object at rest will remain at rest unless acted upon by an external force.” The term “resistance to change in motion” is a simplified way of expressing inertia because it emphasizes the object’s reluctance to alter its motion unless influenced by an outside force.
Inertia is directly related to an object’s mass. The larger the mass, the greater the inertia, meaning that heavier objects are more resistant to changes in motion compared to lighter objects. This is why it is harder to push a heavy object and get it to move or stop compared to a lighter one.
To clarify the other statements:
- Inertia depends on the size of an object – This is not quite accurate. Inertia depends on mass, not the physical size. Two objects of the same size can have different inertia if their masses are different.
- Inertia is proportional to speed – Inertia is independent of speed. It is a property of the object itself, not related to how fast it is moving. Whether an object is moving slowly or fast, its inertia remains constant as long as its mass stays the same.
- Inertia is a vector quantity – This is incorrect because inertia is a scalar quantity, not a vector. It does not have a direction, but simply describes how much an object resists changes to its state of motion.
Here is the image visualizing the concept of inertia, showing how heavier objects are more resistant to changes in motion compared to lighter ones. The arrows indicate the resistance to movement, illustrating the idea that inertia prevents objects from easily changing their state of rest or motion.