FORCES Flashcards
Force
It is a push or a pull exerted on one object by another object.
Forces can change….
The velocity of the object (in magnitude and/or in direction)
Contact force
It is a force that requires physical contact between two objects.
Field force
It is a force that does not require physical contact between the two objects.
External force
It is a force originated from outside of the object in which it is applied.
Internal force
It is a force originated from inside of the object in which it is applied.
In human body, internal forces can be classified as active and passive.
Active force
It is a force generated inside of the body by stimulated muscle (voluntarily or not)
Passive force
It is a force generated inside of the body by tension in stretched periarticular connective tissues, including the intramuscular connective tissues, ligaments, and joint capsules.
Compressive force
It is a force that shrinks the body.
Muscles do ONLY compressive forces.
Tensile force
It is a force that elongates the body.
Eccentric force
It is a force that generates a bending in the body creating compressive stress (internal force) on one side and tensile stress on the opposite side.
Tangential force
It is a force parallel to the surface of the body.
Net force
It is the sum of all the external forces action on the object.
First law of Newton
An object at rest stays at rest and an object in motion stays in motion with constant velocity unless acted upon by a net external force.
Second Law of Newton
If an object has a non-zero net force acting on it, it accelerates in the direction of the net force.
Inertia
It is the tendency of a body to remain at rest or in motion with constant velocity.
Mass
It represents the amount of matter in an object, and it is a measure of the inertia of the object.
Weight
It is the force of gravityexerted on an object.
Gravitational force
It is the force exerted by the Earth on an object.
Third law of Newton
If an object A exerts a force on object B, then object B must exert a force of equal magnitude and opposite direction back on object A.
Normal force
It is a force perpendicular to the surface of contact.
Frictional force
It is theforceresisting the relative motion of solid surfaces sliding against each other (or trying to do it).
Friction depends upon the nature of the two surfaces
and upon the degree to which they are pressed together.
The friction force applies in the plane of the surface of contact but opposes the motion (or intended motion) of an object.
Theforce of static friction
It is a force between two surfaces thatprevents those surfaces from sliding across each other.
Theforce of kinetic friction
It is a force that always opposes the sliding motion and tries toreduce the speed at which the surfaces slide across each other.
Tension
It is a pulling force applied by a cord, wire, cable, string, rope…
Distributed force system
It is a system in which the load is not uniformly distributed over the area of the surface of contact.
Pressure
It is equal to total applied force perpendicular to the surface divided by the area of the surface over which the force is applied.
