FORCE
What is Force?
In physics, a force is any interaction that, when unopposed, will change the motion of an object. A force can cause an object with mass to change its velocity (which includes to begin moving from a state of rest), i.e., to accelerate.
Force can also be described intuitively as a push or a pull. A force has both magnitude and direction, making it a vector quantity. It is measured in Newtons (N) in the International System of Units (SI).
Key Concepts Related to Force:
Newton's Laws of Motion: These three laws form the foundation of classical mechanics and describe the relationship between a body and the forces acting upon it, and its motion in response to those forces.
A) 1st Law (Inertia): An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
B) 2nd Law (F=ma): The acceleration of an object is directly proportional to the net force acting on the object, is in the same direction as the net force, and is inversely proportional to the mass of the object. (Force = mass × acceleratio
n)
C) 3rd Law (Action-Reaction): For every action, there is an equal and opposite reaction.
Net Force: The net force is the vector sum of all the forces acting on an object. It is the net force that determines the object's acceleration.
Types of Forces:
Forces can be broadly classified into two categories:
1. Contact Forces: These forces result from direct physical contact between objects. Examples include:
a) Applied Force: A force applied to an object by a person or another object. (e.g., pushing a box)
b) Frictional Force: A force that opposes motion when two surfaces slide against each other.
b1) Static Friction: The force that prevents an object from starting to move
b2) Kinetic Friction: The force that opposes the motion of a moving object.
c) Tension Force: The force transmitted through a string, rope, cable, or wire when it is pulled tight by forces acting from opposite ends.
d) Normal Force: The support force exerted upon an object that is in contact with a stable object. It is perpendicular to the contact surface.
e) Air Resistance Force: A type of frictional force that acts upon objects as they travel through the air.
e) Spring Force: The force exerted by a compressed or stretched spring upon any object that is attached to it.
2. Non-Contact Forces (Field Forces): These forces act through a distance without physical contact. Examples include:
a) Gravitational Force: The force of attraction between any two objects with mass. It is responsible for the weight of objects and the orbits of planets.
b) Electromagnetic Force: The force between electrically charged objects. It encompasses both electric and magnetic forces and is responsible for many everyday phenomena like light, radio waves, and chemical bonding.
c) Electric Force: The force between charged particles.
d) Strong Nuclear Force: The force that holds the nucleus of an atom together. It is the strongest of the four fundamental forces but acts over very short distances.
e) Weak Nuclear Force: The force responsible for radioactive decay. It is weaker than the strong nuclear force but stronger than gravity.
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