MOD 1-Force And Friction - Module 1 Force And Friction A force is a push or pull upon an object resulting from the object's interaction with another

# MOD 1-Force And Friction - Module 1 Force And Friction A...

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Module 1 Force And Friction A force is a push or pull upon an object resulting from the object's interaction with another object. Whenever there is an interaction between two objects, there is a force upon each of them. When the interaction ceases, the two objects no longer experience the force. Forces only exist as a result of an interaction. Force is a quantity which is measured using the standard metric unit known as the Newton . For simplicity sake, all forces (interactions) between objects can be placed into two broad categories: contact forces, and forces resulting from action- at-a-distance Contact forces are those types of forces which result when the 1
two interacting objects are perceived to be physically contacting each other. Examples of contact forces include frictional forces, tensional forces, normal forces, air resistance forces, and applied forces. Action-at-a-distance forces are those types of forces which result even when the two interacting objects are not in physical contact with each other, yet are able to exert a push or pull despite their physical separation. Examples of action-at-a-distance forces include gravitational forces. For example, the sun and planets exert a gravitational pull on each other despite their large spatial separation. Even when your feet leave the earth and you are no longer in physical contact with the earth, there is a gravitational pull between you and the Earth. Electric forces are action-at-a-distance forces. For example, the protons in the nucleus of an atom and the electrons outside the nucleus experience an electrical pull towards each other despite their small spatial separation. 2
E xamples of contact and action-at-distance forces are listed in the table below. Contact Forces Action-at-a-Distance Forces Frictional Force Gravitational Force Tension Force Electrical Force Normal Force Magnetic Force Air Resistance Force Applied Force Spring Force Type of Force (and Symbol) Description of Force Applied Force F app An applied force is a force which is applied to an object by a person or another object. If a person is pushing a desk across the room, then there is an applied force acting upon the object. The applied force is the force exerted on the desk by the person. 3
Gravity Force (also known as Weight) F grav The force of gravity is the force with which the earth, moon, or other massively large object attracts another object towards itself. By definition, this is the weight of the object. All objects upon earth experience a force of gravity which is directed "downward" towards the center of the earth. The force of gravity on earth is always equal to the weight of the object as found by the equation: Fgrav = m * g where g = 9.8 m/s2 (on Earth) and m=mass in kg Normal Force F norm The normal force is the support force exerted upon an 4
object which is in contact with another stable object. For example, if a book is resting upon a table top, then the surface is exerting an upward force upon the book in order to support the weight of the book. On occasions, a normal force
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