What is force
and what does it mean
So contact forces are types of forces which results when the two interacting objects are perceived to be physically contacting each other. while non-contact force is any force applied to an object(or body) by another body that has not indirect contact with each other.
Gravity is a force of attraction between two objects. All objects with mass have gravity. Gravity acts like a magnet - pulling objects together. What causes gravity is not really known.
So for example the Earth has gravity. Gravity is something that holds everything close to this planet. Trees, water, animals, buildings, and the air we breathe are all held here by gravity. All of the planets, the stars and the moons of the universe have gravity. Even our own bodies have gravity. The Earth's gravity is far stronger than our own so we don't notice the gravity our bodies possess.
Some of the things that gravity is affected by are the size and proximity of objects. The Earth and the moon have a stronger pull on each other than the Earth and say... Jupiter because the Earth and moon are closer to one another. Earth has a stronger pull than the moon because it is larger, so there is more pull on our bodies here on the Earth than astronauts who have gone to the moon would have while they are visiting there. We don't actually "feel" gravity. We only feel the effects of trying to overcome it by jumping or when we fall.
Air resistance is another word for drag.
It is the forces that are in opposition to the relative motion of an object through the air.
Drag forces act opposite to the oncoming flow velocity. Drag, unlike other resistive forces, depends directly on velocity.
Newton’s 3 Laws
Newton's first law of motion states: A body in motion tends to remain in motion, a body at rest tend to remain at rest unless acted on by an outside force.
So, if an object is moving - its inertia (mass) will tend to keep it in motion, and if something is at rest, its inertia will tend to keep it at rest.
Newton's second law of motion states that a force, acting on an object, will change its velocity by changing either its speed or its direction or both.
If your basketball goes rolling into the street and is hit by a bike, either the ball will change direction or its speed or both. It will also be true of the bike.
The third law
It states that for every force and action, there is an equal and opposite reaction.
This is what causes a cannon to recoil when it fires. The 'kick' from the firing of the ammunition is what makes the cannon jump backwards.