Newton's First Law of Motion

Study Notes

Newton's First Law of Motion

This law, also known as the law of inertia, states that an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
Inertia is the tendency of an object to resist changes in its motion. More massive objects have more inertia than less massive objects. This means it takes more force to change the motion of a massive object compared to a less massive one.
The law describes the behavior of objects when there is no net force acting on them.
A net force is the overall force acting on an object, calculated by considering all the forces pushing and pulling on it. If the net force is zero, the object will maintain its current state of motion.
An example includes a book resting on a table. The book is at rest, and the forces acting on it—gravity pulling it down and the table pushing it up—are balanced, resulting in a net force of zero. Hence, the book remains at rest.
If the table is removed, gravity becomes the unbalanced force and causes the book to fall.
Another example is a hockey puck sliding across a frictionless ice rink. If there are no external forces (like the hockey stick), the puck will continue moving at a constant speed in a straight line, forever, according to the law.
In reality, friction and air resistance are always present, slowing the puck. This demonstrates that the law holds true ideally in idealized conditions. However, it highlights the importance of considering ALL forces that could affect motion.
The first law is fundamental to understanding motion because it describes the basic relationships between forces and motion.

Description

Explore the principles of Newton's First Law of Motion, also known as the law of inertia. This quiz covers how objects behave in the absence of net forces and introduces the concept of inertia with examples. Test your understanding of force, motion, and rest!