Newtonian mechanics is a branch of physics that describes the motion of objects under the influence of forces. It is based on the three laws of motion developed by Isaac Newton in the 17th century.
The three laws of motion are:
- An object at rest will remain at rest, or if in motion, will remain at a constant speed and in a straight line unless acted upon by an external force.
- The acceleration of an object is directly proportional to the net force acting on it, and inversely proportional to its mass.
- For every action, there is an equal and opposite reaction.
- These laws can be used to describe a wide range of phenomena, from the motion of planets to the behaviour of fluids and the propagation of waves. They are also applied in many fields, including engineering, medicine, and astronomy.
- Newtonian mechanics predicts the motion of objects with high accuracy. However, it has limitations; for example, it cannot explain the behaviour of light at atomic and subatomic levels, where light behaves as both a wave and a particle—something Newtonian mechanics cannot describe.
- Despite its limitations, Newtonian mechanics remains a crucial and useful theory. It is applied in many fields and has greatly deepened our understanding of the universe.
Here are examples of Newtonian mechanics in action:
- When you throw a ball, the ball accelerates due to the force of gravity.
- When you ride a bike, you need to pedal to keep moving forward because of the force of friction.
- When you sit in a chair, the chair exerts an upward force on you that balances the downward force of gravity.
- When you jump off a cliff, you accelerate due to gravity until you hit the water.