Moving and Energy transfer Flashcards
how is energy measured
energy is measured in joules (j) and kilojoules (kj) 1000j = 1kj, it takes 4.2j of energy to heat 1ml of water 1 degree
what 2 main types of energy
potential (anything with stored energy, food energy and fuel energy in chemical bonds, gravitational energy in height, nuclear energy stored in the nucleus, and elastic energy stored potential form an object being deformed). kinetic (anything that moves, heat energy particles vibrate, electrical energy electrons move, mechanical energy parts move, electromagnetic waves)
what is energy
the ability to do work
what is work
energy transfer that occurs when an object is moved over a distance by an external force. the transfer of mechanical energy from one object to another. when no work is being done energy is conserved
what is the law of conservation of energy
energy cannot be created or destroyed
what is the difference between a transfer and transform of energy
transfer is when energy moves from place to place (e.g heat to body)
transform is when energy changes forms (e.g electrical to light)
what are the 3 types of transfer energy
convection (circular motion through fluid)
conduction (objects touching each other)
radiation (through light rays)
what happens when water is heated
the particles start to moves due to kinetic energy absorbed by the element
what is the difference between heat and temperature
heat is the total amount of heat energy (more hot water=more heat)
temperature is the average heat energy of something
what is a circuit
a circuit is a path from one side of a power source (battery) to the other
what are the primary keys of a circuit diagrams
file:///C:/Users/rhawkins.13/Pictures/Screenshots/Screenshot%202023-11-06%20224548.png
(put in browser)
what is electricity
electricity is the movement of electrons through atoms. if a wire becomes apart of a circuit the electrical field produced by the power sources exerts a force on the electric charge, the atoms don’t move but the electrons do
what is current
current is a measure of the number of electrons flowing through a circuit every second, this is measured in amps
what is voltage
is the amount of available energy to push thee current of electrons and is supplied by things like batteries. voltage is also used to measure the amount of energy released by an energy user e.g. globe (shit measured in volts V)
what is resistance
resistance is something that prevents the flow of electrons (e.g. resistance converts electrical energy into light and heat) (measured in ohms)
what is ohms law
is the equations that helps to find out current, resistance, and voltage
V=IR
I=V/R
R=V/I
V=voltage
I=current
R=resistance
what is a series circuit
is if you follow the circuit diagram from one cell to the other, you should pass through all the components with no other branches
what is a parallel circuit
components are connected via branches of the circuit. unlike the series circuit, if a component breaks then the circuit will keep working
what is wasted energy.
When energy is transferred and transformed, e.g. from electric to light in a light bulb, a LOT of energy is transformed into unwanted forms. if an old incandescent bulb needs 100J of energy and produces 10J of energy then it is 10% efficient
how to find efficiency of something
output/ input x 100%
what is the most efficient renewable energy
wind=62%, hydroelectric=21%
hydro=solar 17%
how is electricity generated
When a coil of wire is rotated through a magnetic field the magnets push and pull on electrons. This generates current and is how 90% of our electricity is generated.
All electricity - (except solar) is generated by moving a conductor (wound in a coil) in a magnetic field. Something is burnt to give off heat to boil water and the steam drives the copper coil of wire round and round in a magnetic field. Pushing electrons along wires. Australia burns coal, Europe reacts uranium, New Zealand uses falling water. At Condong, burning sugar cane waste produces ⅓ of Tweed Valley’s electricity.
which effect do solar panels use
the photoelectric effect
what is inertia
Inertia is the tendency of an object to resist ANY change in motion. All objects have inertia, whether they are moving or not. objects with more mass will have greater inertia. Because of inertia, a resting object will remain at rest. because of inertia, an object will keep moving. To change the motion of an object, inertia must be overcome by a force acting on the object.
what are some examples of inertia
When pulling a Band-Aid off, it is better to pull it fast. Your skin will remain at rest due to inertia, and the force pulls the Band-Aid off.
If pulled quickly, a tablecloth can be removed from underneath the dishes
Seat belts tighten in a car when it stops quickly
what is newtons first law
“An object will remain at rest or in uniform notion in a straight line unless acted upon by an unbalanced force”
Anything that is moving will keep moving at the same speed and in the same direction unless a force changes it.
Inertia explains why you sometimes ‘feel’ lighter or heavier when in a lift as it first moves off or slows to a stop.
It also tells why you ‘move sideways’ when a car corners: you keep trying to travel in a straight line.
what is an unbalanced force
the force applied in one direction is greater than the force applied in the opposite direction.
what is newtons second law
“An object will accelerate if an unbalanced force is applied to it. Its acceleration will depend on the size of the force and the mass of the object”.
this law has a formula,
force=mass(kg) x acceleration(m/s/s)
f=ma
m=f/a
a=f/m
what is newtons third law
“To every action (force) there is an equal and opposite reaction (force)”.
what is speed
Speed is the rate at which
distance is covered—the amount of distance covered for
each unit of time. Commonly used units of time are
hours (unit symbol h) and seconds (s).
÷3.6 km/h ⎯⎯→ m/s
←⎯⎯
x3.6
what is velocity
Velocity is speed in a given
direction. Velocity has the same relationship to speed
that displacement has to distance—they are measured
in the same units, but add information about direction.
average velocity = displacement/
time
what is a distance time graph
Distance–time graphs show the total distance
travelled by an object as time progresses. Time is always placed on the horizontal axis and distance on the vertical. Steep graphs indicate that the object is covering more
distance and travelling faster than flatter graphs.
what is a speed time graph
A graph of speed against time gives another picture of what is happening in the motion of an object. As
before, time is placed on the horizontal axis. If the
object is getting faster, the graph rises. If it is slowing,
the graph falls. Constant speed gives a flat graph.
The area under a speed–time graph gives the
distance that the object has travelled up to
that point.
how to find gradient of graphs
rise/run
what is the speed, distance and time formula
speed=distance x time
d=st
s=d/t
t=d/s
