Newton's Laws of Motion and Dynamics
This section delves into the fundamental principles of dynamics, focusing on Newton's 1st, 2nd, and 3rd laws of motion.
Definition: Newton's first law of motion states that an object will remain at rest or travel in a straight line at a constant velocity if the forces acting on it are balanced.
Definition: Newton's second law of motion, also known as the law of force and acceleration, states that if the forces acting on a mass are unbalanced, the mass will accelerate. It is expressed mathematically as F = ma.
Definition: Newton's third law of motion, often called the law of action and reaction, states that for every action force, there is an equal but opposite reaction force.
The page also covers the concept of free fall:
- Free fall occurs when an object is acted upon only by the force of gravity (weight)
- Air resistance increases as an object accelerates
- Terminal velocity is reached when air resistance equals weight
- At terminal velocity, the object falls with constant velocity due to balanced forces (Newton's 1st Law)
Example: A practical application of Newton's laws is demonstrated through the explanation of horizontal projectiles:
- Horizontally, the object moves with constant velocity
- Vertically, the object moves with constant acceleration
Highlight: The motion of satellites is explained using these principles:
- A satellite continually accelerates vertically towards the ground
- Its high horizontal velocity causes the Earth to curve away from it as quickly as it falls
The section concludes with an introduction to energy concepts:
- Work done: A measure of energy transformed
- Gravitational potential energy: Energy gained by an object raised off the ground
- Kinetic energy: Movement energy of an object at a given moment
- Power: Energy transferred or used per unit time
Vocabulary:
- Work done (W): Measured in Joules (J) or Newton-meters (Nm)
- Gravitational potential energy (Ep): Ep = mgh, where m is mass, g is gravitational acceleration, and h is height
- Kinetic energy (Ek): Ek = ½mv², where m is mass and v is velocity
Highlight: The conservation of energy principle is emphasized: Energy cannot be created or destroyed, only transformed from one type to another.
