ns test Flashcards
ns test
what is a force?
a force is a push,pull and twist exerted on an object
what is the unit to measure force?
Newton (N)
what is contact force?
a force where the two bodies must be touching
what is non-contact force?
when two bodies do not have to be touching
what is friction?
when 2 objects must be touching and an external force must be applied on the object in an attempt to move it
what are three type of friction?
sliding friction,rolling friction and fluid friction
what is tension?
tension is a stretching force that pulls on a material
what is compression?
compression is a pushing force that squeezes a material
what is gravitational force?
when the earth exerts a force of attraction (gravity) on all objects
what is magnetic force?
attraction or repulsion that arises between electrically charged particles because of their motion
what is static electricity?
an imbalance of electric charges on the surface of an object
what is a cell in electric cells?
a cell is something that gives off an electric current as a result of a chemical reaction
what is current?
current is the rate of flow of electric charge
what is the instrument used to measure current called?
an ammeter (A)
what is voltage?
voltage is electrical potential energy and measured in volts
what is the instrument used to measure voltage called?
an voltmeter
what is a resistor?
to limit the flow of electric current
what are series circuits?
any electrically conducting pathway comprising an electric circuit along which the whole current flows through each component.
what are parallel circuits?
A parallel circuit has two or more paths for current to flow through
what are safety with electricity?
the practice of handling and maintaining electrically powered equipment to prevent incidents
what are the use of fuses?
protect electrical circuits from power surges, short circuits, and other issues by breaking the circuit when too much current passes through:
what are the use of circuit breakers?
A circuit breaker is an electrical switch designed to protect an electrical circuit from damage caused by overcurrent/overload or short circuit
what are earth leakage systems?
An earth-leakage circuit breaker (ELCB) is a safety device used in electrical installations with high Earth impedance to prevent shock.
what the use of the three wire in a three-pin
plugs?
brown wire-the live wire
blue wire-the neutral wire
green/yellow-earth wire
what are the use of the earth wire?
protects people from electrocution and damage to electrical appliances
what is the national grid?
The national electricity grid is a system to deliver electricity around the country
what is the cost of electrical power?
Electricity Cost = Electricity Consumption (kWh) x Tariff Rate per unit
what is the earth as a system?
The biosphere (life), the lithosphere (land), the hydrosphere (water) and the atmosphere (air)
what is the term of lithosphere?
the rigid, outermost layer of the Earth’s rocks and minerals, which consists of the crust and upper mantle
what is the term of biosphere?
the region of the planet where organisms live
what is the term of hydrosphere?
A hydrosphere is the total amount of water on a planet.
what is the term of atmosphere?
a layer of gases and suspended solids that surrounds a planet or other celestial body
what is the rock cycle?
the processes through which the three main rock types (igneous, metamorphic, and sedimentary) transform from one type into another.
what is igneous rock?
they are formed from the cooling and solidification of molten (melted) rock
what is sedimentary rocks?
formed from deposits of pre-existing rocks or pieces of once-living organism that accumulate on the Earth’s surface
what is metamorphic rock?
Rocks that have undergone changes in their physical and chemical properties due to intense heat and pressure deep within the Earth’s crust.
what is mining of mineral resources?
Mining is the extraction of valuable geological materials and minerals from the surface of the Earth
what is extracting ores?
the process of removing valuable metals or minerals from rock that’s buried underground, or ore, and treating it to obtain the metal
what is surface mining?
Surface mining refers to the removal of the terrain surface to access minerals underneath
what is underground mining?
Underground mining is a method of extracting minerals, rocks, and other materials from beneath the earth’s surface
what is the birth of a star?
stars form from collapsing clouds of gas and dust,initating nuclear fusion that power the star
