Newton's First Law Definition and Examples

📚 Quick Study Guide

• 🍎 Definition: Newton's First 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: Inertia is the tendency of an object to resist changes in its state of motion. The more massive an object is, the greater its inertia.
• ⚖️ Balanced Forces: When all forces acting on an object are balanced, the net force is zero, and the object's motion remains constant.
• 🚀 Unbalanced Forces: An unbalanced force results in acceleration or deceleration. $F = ma$ (Newton's Second Law) describes this relationship, but the First Law sets the stage.
• 🌍 Examples: A book sitting on a table remains at rest unless someone picks it up. A hockey puck sliding on ice continues to slide until friction slows it down.

🧪 Practice Quiz

1. What is another name for Newton's First Law?
   1. Law of Acceleration
   2. Law of Universal Gravitation
   3. Law of Inertia
   4. Law of Conservation of Energy
2. According to Newton's First Law, what happens to an object in motion if no unbalanced forces act on it?
   1. It speeds up.
   2. It slows down.
   3. It changes direction.
   4. It continues moving with the same speed and direction.
3. Which property of an object determines its inertia?
   1. Volume
   2. Mass
   3. Density
   4. Weight
4. What is the net force on an object in equilibrium?
   1. Equal to its weight
   2. Zero
   3. Equal to its mass
   4. Dependent on its velocity
5. A hockey puck slides across the ice. What force eventually causes it to slow down and stop?
   1. Applied Force
   2. Normal Force
   3. Friction
   4. Gravity
6. If you are standing on a bus and it suddenly stops, what happens to your body due to inertia?
   1. You move backward.
   2. You stay in place.
   3. You fall to the side.
   4. You move forward.
7. An object is at rest. Which of the following statements must be true according to Newton's First Law?
   1. There are no forces acting on it.
   2. The net force acting on it is zero.
   3. It will eventually start moving.
   4. It has a non-zero acceleration.