Forces

Post on 10-May-2015

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Transcript of Forces

FORCEAND pRESSURE

- playing a guitar - scrubbing the floor - sawing wood - rowing a boat

• A pull is when we apply a force to move an object towards our body

• A force to move an object away from our bodies

FORCE

A force is a push or a pull or both. A force cannot be seen but we can feel andobserve the effects of the force.

PUSH PULL

COMBINATION OF PUSH AND PULL

ForceContact

Muscular Frictional

Non Contact

Gravitation

al

Magnetic

Electrostatic

Contact forcesContact forces are those types of forces which result when the two interactingobjects are perceived to be physically contacting each other. Examples of contact forces include Frictional forces Muscular forces

Frictional ForceThe friction force is the force exerted by a surface as an object moves across it or makes an effort to move across it. There are at least two types of friction force - sliding and static friction. For example, if a book slides across the surface of a desk, then the desk exerts a friction force in the opposite direction of its motion.

Rowing a boat

Muscular ForceThe muscular force comes from muscles of man

or animals. Every physical activity comes with a use a muscle , Hence they are muscular forces.

RUNNING

Scrubbing the floor

Sawing wood

Non Contact forces

Non Contact 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 Non Contact forces include gravitational forces.

Gravitational ForceThe 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.

Magnetic ForceAttraction or repulsion that arises between electrically charged particles because of their motion; the basic force responsible for the action of electric motors and the attraction of magnets for iron. Electric forces exist among stationary electric charges; both electric and magnetic forces exist among moving electric charges.

Horse shoe magnet… Bar Magnet…

Electrostatic Force The force exerted by stationary objects bearing electric charge on other stationary objects bearing electric charge. If the charges are of the same sign, then the force is repulsive; if they are of opposite signs, the force is attractive. The strength of the force is described by Coulomb's law. Also called electrostatic force.

Stretch a rubber band

After

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