Basic Physics
Newton's Laws of Motion:
- Newton's First Law states that an object at rest will stay at rest and an object in motion will remain in motion, with a constant velocity, unless acted on by an unbalanced force. This is also known as the Law of Inertia.
- Newton's Second Law describes how the velocity of an object changes when it is subjected to an external force. It can be mathematically expressed as Force = mass x acceleration (F = ma).
- Newton's Third Law states that for every action, there is an equal and opposite reaction. This means that any force exerted on a body will create a force of equal magnitude but in the opposite direction on the object that exerted the first force.
Concept of Force:
- A force is a push or pull upon an object resulting from the object's interaction with another object. The SI unit of force is the Newton (N).
- Force can cause an object to move, stop moving, or change direction.
- There are various types of forces including friction, gravity, normal force, and tension.
Motion and Acceleration:
- Motion refers to any movement or change in position or place. It can be described in terms of displacement, distance, velocity, acceleration, time and speed.
- Acceleration is a measure of how much the velocity of an object changes in a certain time period. It is calculated using the formula acceleration = (final velocity - initial velocity)/time (a = (v - u)/t).
- The unit for acceleration is m/s^2 and it can be a positive or negative value (deceleration).
Momentum:
- Momentum is the mass of an object multiplied by its velocity. It is calculated using the formula momentum = mass x velocity (p = mv).
- The unit for momentum is kg m/s.
- The Law of Conservation of Momentum states that the total momentum of a system of objects is constant if no external forces are acting on it.
Gravitational Field and Weight:
- A gravitational field is a region of space around a mass where another mass would feel a force of attraction.
- The weight of an object is the force of gravity acting on its mass. Weight (W) can be calculated using the formula weight = mass x gravity (W = mg).
- Weight is a force and is measured in Newtons (N), and it is different from the mass of an object which is a scalar quantity measured in kilograms (kg).
Centripetal Force and Circular Motion:
- Centripetal force is the force that keeps an object moving in a circular path. It acts inwards towards the centre of the circle.
- The formula for centripetal force is F = mv^2/r, where m is the mass of the object, v is the velocity and r is the radius of the circular path.
- Circular motion is a type of motion where an object moves along a circular path or in a circular manner.