Forces In Action ch. 8 Flashcards
Contact Force
When one object comes in contact with another object
Eg.
1.Brushing your hair
2. Hitting a gold ball
No Contact Force
The motion and shape of objects can be changed without touching them with anything
Eg.
1. When you drop a tennis ball, it speeds up as it falls through the air.
Gravity
- The Force of gravity pulls down
- Gravity is a non-contact force
- Other types of Non-contact force involve magnetic force and electro static force
Force
A Force is a push or pull in a particular direction
(They are occurring around us all the time)
1. Pull the door open
2. Pushing a couch
3. The force you use to push the pen open and close
Permanent Magnets
Permanent Magnets are magnets that retain their magnetism when removed from other magnets
Temporary Magnets
Temporary Magnets are magnets that loose their magnetism when removed from another magnet.
Attraction
The force by which one object attracts another
Repulsion
An opposing force
Magnetic fields
Magnetic fields are the areas where the magnetic force acts
Domains
Domains are little compartments in an object that make thr object magnetic
Electromagnet
An electromagnet is a coil of wire wrapped around an iron coil
Nucleas
roundish structure inside cells that acts as the control centre for the cell. Plural = nuclei
Electrons
Very light, negatively charged particles inside an atom. Electrons move around the central nucleus of an atom
Protons
tiny, but heavy, particle found in the nucleus of an atom. Protons have a positive electrical charge
Positive electric charge
the charge on an atom or object with fewer electrons than protons
Neutrons
tiny, but heavy, particles found in the nucleus of an atom. Neutrons have no electrical charge
Neutral
having the same number of protons and electrons
Static electricity
a build-up of charge in one place
Insulators
materials that do not allow electric charge to flow through them
Conductors
materials that allow electric charge to flow through them
Lightning rods
conductive metal rod, often attached to the top of tall buildings. Lightning rods help to keep buildings safe from lightning strikes
Mass
a measure of the amount of material in an object of substance
Weight
a measure of the size of the gravity force pulling an object towards the centre of a massive body, such as the Earth. The weight of an object depends on the object’s mass
Newton
the unit for measuring forces
Air resistance
the force of air pushing on an object as the object moves through the air
Terminal speed
the constant speed reached by a falling body. A body reaches terminal speed when the force of gravity pulling it down is balanced by the air resistance pushing against it
Friction
a force that acts against the movement of an object. It occurs between any surfaces that are touching and trying to move past each other
Traction
type of friction used to assist movement
Lubricants
Substance with large particles that can slide easily over each other. Lubricants are used between surfaces that rub against each other to reduce wear and increase motion between the surfaces
Fluid
a substance that flows and has no fixed shape. Gases and liquids are fluids
Streamlined
Shaped so that drag through a fluid is minimised
Mass
a measure of the amount of material in an object of substance
Weight
a measure of the size of the gravity force pulling an object towards the centre of a massive body, such as the Earth. The weight of an object depends on the object’s mass
Newton
the unit for measuring forces
Air resistance
the force of air pushing on an object as the object moves through the air
Terminal speed
the constant speed reached by a falling body. A body reaches terminal speed when the force of gravity pulling it down is balanced by the air resistance pushing against it
Friction
a force that acts against the movement of an object. It occurs between any surfaces that are touching and trying to move past each other
Traction
type of friction used to assist movement
Lubricants
Substance with large particles that can slide easily over each other. Lubricants are used between surfaces that rub against each other to reduce wear and increase motion between the surfaces
Fluid
a substance that flows and has no fixed shape. Gases and liquids are fluids
Streamlined
Shaped so that drag through a fluid is minimised
Buoyancy
a force which keeps objects floating
Surface tension
the ‘firmness’ of the surface of a liquid created by the attraction between particles at the surface. The surface acts like an elastic skin
