Examples of Newton's First Law of Motion

📚 Quick Study Guide

• 🍎 Newton's First Law (Law of Inertia): 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: The tendency of an object to resist changes in its state of motion. More mass = more inertia.
• 🚗 Examples in Everyday Life: A car stopping suddenly, a ball rolling until friction stops it, and a skater gliding on ice.
• 🧮 Mathematical Representation: If the net force ($\vec{F}_{net}$) acting on an object is zero, its velocity ($\vec{v}$) remains constant. $$\vec{F}_{net} = 0 \implies \vec{v} = constant$$
• 💡 Key Concept: Forces are required to *change* motion, not to *maintain* motion.

Practice Quiz

1. Which of the following best describes Newton's First Law?
   1. A) An object in motion stays in motion.
   2. B) An object at rest stays at rest.
   3. C) An object's motion changes only if a net force acts on it.
   4. D) All of the above.
2. A book is sitting on a table. Which statement is true according to Newton's First Law?
   1. A) The book will remain at rest unless a force acts on it.
   2. B) The book will suddenly start moving randomly.
   3. C) The book is constantly experiencing a net force.
   4. D) The book's inertia is zero.
3. What is inertia a measure of?
   1. A) An object's speed.
   2. B) An object's resistance to changes in motion.
   3. C) The force of gravity acting on an object.
   4. D) An object's acceleration.
4. A hockey puck slides across the ice. Eventually, it slows down and stops. Why?
   1. A) Newton's First Law is violated.
   2. B) The puck's inertia decreases.
   3. C) Friction acts as an unbalanced force.
   4. D) The puck runs out of energy.
5. Which of these scenarios best illustrates Newton's First Law?
   1. A) A car accelerates when the driver presses the gas pedal.
   2. B) A ball rolls down a hill, gaining speed.
   3. C) A spacecraft continues moving at a constant velocity in space.
   4. D) A parachutist slows down due to air resistance.
6. If an object is moving with constant velocity, what can you conclude about the net force acting on it?
   1. A) The net force is increasing.
   2. B) The net force is decreasing.
   3. C) The net force is zero.
   4. D) The net force is constant but non-zero.
7. Why do you need to wear a seatbelt in a car?
   1. A) To increase the car's inertia.
   2. B) To provide an external force to stop you from continuing to move forward in a sudden stop.
   3. C) To reduce the car's acceleration.
   4. D) Because seatbelts look cool.