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physics - Coggle Diagram
physics
electromagnetic waves
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are transverse waves; can travel through a vacuum ; travel at exactly the same speed in a vacuum, the speed of light, 300,000,000 m/s.
The transfer of energy by electromagnetic waves is called electromagnetic radiation. The electric and magnetic fields of an electromagnetic wave are areas of electric or magnetic force. The fields can exert force over objects at a distance. An electromagnetic wave begins when an electrically charged particle vibrates.
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rafdiation
The behavior of EM radiation and its interaction with matter depends on its frequency, and changes qualitatively as the frequency changes. Lower frequencies have longer wavelengths, and higher frequencies have shorter wavelengths, and are associated with photons of higher energy.
The higher the frequency of the radiation, the more damage it is likely to cause to the body: microwaves cause internal heating of body tissues. infrared radiation is felt as heat and causes skin to burn.
Ultraviolet waves can cause damage to skin cells and eyes, and increase the risk of skin cancer. X-rays and gamma rays can cause the mutation of genes, which can lead to cancer.
There are three main types of ionising radiation emitted from the unstable nuclei of radioactive atoms - these are alpha, beta and gamma radiation.
radiation
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radiation will ionise your DNA (turning it into ions by removing an electron or multiple electrons). This can cause cancer.
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Background radiation is a measure of the level of ionizing radiation present in the environment at a particular location which is not due to deliberate introduction of radiation sources. Background radiation originates from a variety of sources, both natural and artificial.
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vectors and scalars
mass and weight
Mass is a measure of how much matter there is in an object, while weight is a measure of the size of the pull of gravity on the object. Mass is the amount of matter in an object. Mass is measured in kilograms (kg). Weight is a force due to the pull of gravity on an object.
Vector quantities have two characteristics, a magnitude and a direction. Scalar quantities have only a magnitude.
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velocity and speed
Speed is the time rate at which an object is moving along a path, while velocity is the rate and direction of an object's movement. Put another way, speed is a scalar value, while velocity is a vector.
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momentum
the quantity of motion of a moving body, measured as a product of its mass and velocity.
energy
the capacity for doing work. It may exist in potential, kinetic, thermal, helectrical, chemical, nuclear, or other forms.
waves
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Speed is distance over time, so v = λ / T
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newton's second law
Acceleration is the rate of change of velocity. It is the amount that velocity changes per unit time.
The acceleration of an object depends on the mass of the object and the amount of the force applied to it.
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mass and weight
Mass is a measure of how much matter there is in an object, while weight is a measure of the size of the pull of gravity on the object.
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stopping distance
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Reaction times vary from person to person, but are typically 0.2 seconds (s) to 0.9 s. it can be affected by things like alcohol tiredness and other things
stopping distance, thinking distance and braking distance
thinking distance is the distance a vehicle travels in the time it takes for the driver to apply the brakes after realising they need to stop. braking distance is the distance a vehicle travels in the time after the driver has applied the brake.
braking distance
braking distance is affected by the quality of the brakes, quality of the road and the weather.
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atoms
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structure of an atom
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A typical atom has the order of magnitude of 10 -10 m. A small molecule has the order of magnitude of 10 -9 m.
inside an atom
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elements have different numbers of protons and different number of electrons and different numbers of protons
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orbit
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When an electron absorbs energy, it jumps to a higher orbital. This is called an excited state. An electron in an excited state can release energy and 'fall' to a lower state.
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newtons third laws
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the condition of a system when neither its state of motion nor its internal energy state tends to change with time.
a baseball forces the bat to the left; the bat forces the ball to the right. Together, these two forces exerted upon two different objects form the action-reaction force pair.
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momentum
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momentum in a collision
Momentum is of interest during collisions between objects. When two objects collide the total momentum before the collision is equal to the total momentum after the collision (in the absence of external forces). This is the law of conservation of momentum. It is true for all collisions.
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acceleration
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Acceleration does not increase in a free fall. The acceleration on the surface of the earth is approximately equal to 9.8 m/s2. The velocity increases constantly but not the acceleration.
newtons first law
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moving object
on an object that is at a constant velocity and has a resultant force of 0 then it will stay at a constant velocity
if a object is accelerating then it has not got a resultant force of 0 it will carry on accelerating
An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
resultant forces
a resultant force is the name for all of the forces acting on a body which produces a final force which is the resultant force and that is the most powerful one
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refraction
refraction, in physics, the change in direction of a wave passing from one medium to another caused by its change in speed.
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crash hazards
The faster a vehicle travels, the greater the braking force needed to stop it in a certain distance. A greater braking force produces a greater deceleration . Large decelerations may cause the brakes to overheat, and the driver may also lose control of the vehicle.