Fundamental Laws of Motion to Know for AP Physics C: Mechanics

Understanding the Fundamental Laws of Motion is key to mastering mechanics. These laws explain how forces affect motion, energy, and momentum, laying the groundwork for more complex concepts in AP Physics C: Mechanics. Get ready to connect the dots!

1. Newton's First Law of Motion (Law of Inertia)

   • An object at rest stays at rest, and an object in motion stays in motion unless acted upon by a net external force.
   • This law defines inertia, the tendency of an object to resist changes in its state of motion.
   • It implies that the absence of a net force results in constant velocity, including zero velocity.

2. Newton's Second Law of Motion (F = ma)

   • The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.
   • This law quantifies the relationship between force, mass, and acceleration, providing a formula to calculate motion.
   • It emphasizes that greater mass requires a larger force to achieve the same acceleration.

3. Newton's Third Law of Motion (Action-Reaction)

   • For every action, there is an equal and opposite reaction.
   • This means that forces always occur in pairs; when one object exerts a force on another, the second object exerts a force of equal magnitude in the opposite direction.
   • It highlights the interaction between objects and the mutual forces they exert on each other.

4. Conservation of Linear Momentum

   • The total linear momentum of a closed system remains constant if no external forces act on it.
   • Momentum is defined as the product of mass and velocity, and it is a vector quantity.
   • This principle is crucial in analyzing collisions and interactions between objects.

5. Work-Energy Theorem

   • The work done on an object is equal to the change in its kinetic energy.
   • This theorem connects the concepts of work and energy, providing a method to calculate energy changes in a system.
   • It emphasizes that energy can be transferred through work, affecting an object's motion.

6. Conservation of Energy

   • Energy cannot be created or destroyed; it can only be transformed from one form to another.
   • The total energy of an isolated system remains constant over time.
   • This principle underlies many physical processes, including mechanical, thermal, and chemical systems.

7. Principle of Conservation of Angular Momentum

   • The total angular momentum of a closed system remains constant if no external torques act on it.
   • Angular momentum is the rotational equivalent of linear momentum and depends on the distribution of mass and its velocity.
   • This principle is essential in understanding rotational dynamics and systems like spinning objects.

8. Kepler's Laws of Planetary Motion

   • The orbit of a planet is an ellipse with the Sun at one focus (First Law).
   • A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time (Second Law).
   • The square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit (Third Law).

9. Universal Law of Gravitation

   • Every point mass attracts every other point mass with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.
   • This law explains the gravitational force as a fundamental interaction governing the motion of celestial bodies.
   • It provides the foundation for understanding orbits, tides, and other gravitational phenomena.

10. Hooke's Law for Springs

    • The force exerted by a spring is directly proportional to the displacement from its equilibrium position, expressed as F = -kx.
    • This law describes the behavior of elastic materials and is fundamental in understanding oscillatory motion.
    • It highlights the restoring force of a spring, which acts to return the spring to its original position when stretched or compressed.