Balloon Hovercraft:
The small hole in the centre of the CD, forces air to escape from its bottom surface. This creates an
opposite force upwards which lifts the hovercraft off the ground, as per Newton's third law of motion.
For every action there is an equal and opposite reaction. This statement means that, for every force there is a reaction force that is equal in size, but opposite in direction.
That is to say that whenever an object pushes another object it gets pushed back in the opposite direction equally hard.
If we consider a launching rocket, the rocket's action is to push down on the ground with the force of its powerful engines, and the reaction is that the ground pushes the rocket upwards with an equal force. All forces in the universe occur in equal but oppositely directed pairs. There are no isolated forces; for every external force that acts on an object there is a force of equal magnitude but opposite direction which acts back on the object which exerted that external force.
Friction, in day to day affairs, is experienced everywhere. While holding a hammer, holding a pen, walking, driving a car, pushing a cart or even while playing. There are two common types of friction:
- Static friction
- Kinetic friction.
Static friction is the frictional force that exists between surfaces in contact when there is no relative motion. On the other hand, kinetic friction is frictional force that exists between surfaces in contact when there is motion between the two.