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Force Notes. Force : Push or pull that acts on an object. Forces can be : Contact force – one object directly pushes another. Action-at-distance – does NOT involve direct contact. Kinds of Force : Gravitational force – force that pulls objects together without direct impact or contact.
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Force Notes Force: Push or pull that acts on an object. Forces can be: Contact force – one object directly pushes another. Action-at-distance – does NOT involve direct contact. Kinds of Force: Gravitational force – force that pulls objects together without direct impact or contact. Weight – measure of the force of gravity of an object. Electrical force – force that holds + and – particles of an atom together.
Force Notes • Nuclear Force – Force that holds the inside of the nucleus of an atom together. • Fluid Pressure or Buoyant Force – the upward push on matter that is exerted by a liquid. • Frictional Force – a retarding force that occurs when surfaces slide or tend to slide over one another – depends on the kind of material and how much they are pressed together. The direction of friction force is ALWAYS in a direction opposing motion.
Combinations of Forces If the forces acting on an object are balanced, the object will remain at rest –NO motion. If the forces are unbalanced, the object will be placed in motion.
Combination of Forces • Unbalanced forces will cause an object to move in the direction that the greater force is exerting. • Force is measured in Newtons (N). • 1 Newton is equal to the force needed to change the speed of 1 kg mass by 1 m/s2 for the entire time the force is acting on the mass.
Newton’s Laws of Motion First Law – Every object continues in it’s state of rest, or in motion, unless it is compelled to change that state by forces acting on it. Also called the Law of Inertia. Inertia – the tendency of things to resist changes in motion. The amount of inertia an object has is dependent upon how much matter the object consists of (it’s mass). The greater the mass, the greater the inertia. Mass is a measure of the amount of inertia an object has, the harder it is to change it’s state of motion.
Newton’s Laws of Motion Second Law – The acceleration of an object is directly proportional to the net force acting on it. In addition, the direction of the motion of the object is determined by the net force. F = m x a Force = mass x acceleration If no net force is acting on an object, it will remain at rest, or if moving, it will continue moving with a constant speed in a straight line. Force is capable of accelerating an object. The amount of force necessary to accelerate an object is dependent upon the mass of an object. The more the mass, the more force is needed to accelerate an object to the same rate as an object with a smaller mass.
Newton’s Laws of Motion Third Law – Whenever an object exerts a force on a second object, the second object exerts an equal and opposite force on the first. “For every action, there is an equal and opposite reaction.” Forces come in pairs. A force is not a thing on itself but is due to an interaction between one thing and another.