Interactions
Interactions occur between objects and are most easily represented by diagrams. No A push or a pull. The unit of force is the newton (N). occurs by itself, it is always as a result of a pull or push of one body on another. There are several examples:
Reaction force (contact)
An object at rest on a surface experiences Force exerted in the opposite direction to an action force. from the table pushing up on the object. For example, a box on a table - there is the pull of the Earth down on the box and the push of the table up on the box.
Friction (contact)
Two objects sliding past each other experience A force that opposes or prevents movement and converts kinetic energy into heat. forces. For example, a box sliding down a slope.
Air resistance (contact)
An object moving through the air experiences A force of friction produced when an object moves through the air.. For example, a skydiver falling through the air. There is contact between the body of the skydiver and the molecules that make up the air.
When a Force exerted between two objects when they are touching. acts between two objects, both objects experience the same size force, but in opposite directions. This is Newton's Third Law of Motion. So if body "A" pushes on body "B", then body "B" pushes back equally on body "A".
Magnetic force (non-contact)
A magnetic force is experienced by any Able to be magnetised or attracted to a magnet. material in a Area surrounding a magnet that can exert a force on magnetic materials..
Opposite magnetic poles (N鈥揝 or S鈥揘) Objects that tend to move together because of a force between them attract each other. each other:
Like magnetic poles (N鈥揘 or S鈥揝) Objects that tend to push apart because of a force between them repel each other. each other:
Electrostatic force (non-contact)
An A force of attraction between particles with opposite charges. is experienced by any charged Particles, usually ions or electrons, that carry electrical charges. in an Area surrounding an electric charge that may influence other charged particles..
Opposite charges (+ and 鈥) attract:
Like charges (鈥 and 鈥, or + and +) repel:
Gravitational force (non-contact)
A gravitational force is experienced by any The amount of matter an object contains. Mass is measured in kilograms (kg) or grams (g). in a gravitational field.
Masses are attracted towards each other by gravitational force:
The Earth pulls on the satellite (weight) to keep it in orbit. However, the satellite also pulls back with an equal force on the Earth. Because the Earth is so large, this force has such a small effect on the Earth that it is not noticed.
Learn more on gravity in this podcast
Listen to the full series on 91热爆 Sounds.