Energy Unit 1- Forces

External forces

are forces acting on an object from outside its system, affecting its motion or state of rest.

non-contact forces

are forces that do not require contact between objects, such as gravitational, magnetic, and electrostatic forces.

Gravity

is a non-contact force that attracts objects with mass toward each other, specifically pulling them toward the center of the Earth.

Magnet 

is a material or object that produces a magnetic field, which can attract ferromagnetic materials and exert a force on charged particles.

Contact forces

are forces that result from the interaction between objects in physical contact, such as friction, tension, and normal force.

Applied forces

are forces that are applied to an object by a person or another object, influencing its motion or position.

Spring forces

are forces exerted by a compressed or stretched spring, described by Hooke's Law, which states that the force is proportional to the displacement of the spring.

Drag forces

are forces that oppose the motion of an object through a fluid, such as air or water, and are proportional to the object's velocity.

Frictional forces

are forces that resist the relative motion of solid surfaces, fluid layers, or material elements in contact, and depend on the nature of the surfaces and the normal force acting between them.

Normal forces

are the support forces exerted upon an object that is in contact with another stable object, acting perpendicular to the surfaces in contact.

Magnetic forces

are the attractive or repulsive forces between charged particles or magnets, depending on their orientation and charge.

Electric forces

are the attractive or repulsive forces between electrically charged objects, determined by the magnitude and sign of their charges.

Gravitational forces

are the attractive forces between two masses, proportional to the product of their masses and inversely proportional to the square of the distance between their centers.

Static friction

is the force that resists the initiation of sliding motion between two surfaces in contact that are at rest relative to each other.

Sliding friction 

is the force that opposes the relative motion of two surfaces sliding past each other.

Rolling friction

is the resistance encountered when an object rolls across a surface, usually less than sliding friction.

Tension

is the force exerted along a medium, such as a rope or cable, when it is pulled tight by forces acting from opposite ends.

Compression 

is the force that acts to reduce the volume of a material or object, typically by pushing or squeezing it.

Torsion

is the twisting force that causes shear stress in a material, often applied to objects like shafts and beams when torques are applied at opposite ends.

Sheer

stress caused by force acting parallel to a surface.

Bending

is the deformation of a material caused by an external force that induces moments about an axis, resulting in a curvature.

Newton’s First Law of Motion

states that an object at rest stays at rest and an object in motion stays in motion unless acted upon by a net external force.

Newton’s Third Law of Motion

states that for every action, there is an equal and opposite reaction.

Newton’s Second Law of Motion

states that the acceleration of an object is directly proportional to the net external force acting on it and inversely proportional to its mass, often expressed as F=ma.

Plasticity

the ability of a material to undergo permanent deformation without breaking when subjected to stress.

Elasticity

the ability of a material to return to its original shape after the removal of a stress or force.