Paper 1 Flashcards
What is the equation for acceleration
Acceleration(m/s2) = change in velocity (m/s) / time
What is Newton’s 1st law
This says anything that starts, speeds up or slows down needs a resultant force
What is Newton’s 2nd law
This means the larger the resultant force acting on an object the more the object acceleration. The force and acceleration are directly proportional. Acceleration is also inversely proportional to the mass of an object.
Resultant force = mass * acceleration
What is the equation for weight
Weight (N) = mass (kg) * gravitational field strength ( 10)
What is centripetal force
This is where an object is ovine at a constant speed with a changing velocity around a circle. This means the force must act towards the circle
What is inertia
This means that until acted on by a resultant force objects stay at rest and objects moving at a constant velocity will keep moving at that velocity.
What is inertial mass
This measures how difficult it is for an object to change its velocity.
Mass = resultant force / acceleration
What is Newton’s 3rd law
This says that when 2 objects interact the forces they exert on each other are opposite and equal
What is the equation for momentum
Momentum = mass * velocity
What is the equation for resultant force using momentum
Resultant force = change in momentum / time
What is the equation for stopping distance
Stopping distance = thinking distance + braking distance
Name the 8 types of energy
Kinetic, thermal, chemical, gpe, elastic potential, electrostatic, magnetic, nuclear
What is the equation for kinetic energy
Kinetic energy = 0.5 * mass * speed^^2
What does conservation of energy mean
This means energy is never created or destroyed.
What are the 4 ways of transferring energy
Mechanically- a force acting on another, electrically- a charge doing work against resistance, by heating- energy transferred from a hotter to a colder object, and by radiation- energy transferred by waves
What is the equation for the efficiency of an energy transfer
Efficiency = useful energy by device / total energy supplied by device
What do lubricants do to mechanical transfers
They reduce friction so less thermal energy is produced
What are some renewable energy resources
Bio-fuels, Wind, solar, hydro electric and tides
How are bio fuels made
These are made by plant products or animal dung. These can be burnt and produce electricity.
How do tidal barrages produce energy.
These are big dams built across river estuaries. These contain turbines. As the tide fills up the estuary the water moves the turbine. And this turbine generates electricity
What do waves do?
Waves transfer energy from one place to another without transferring matter
What is the amplitude of a wave
This is the displacement from the rest to a trough ( base ) or a crest ( peak)
What is the Wave length?
This is the length of a full cycle of the wave.
What is the frequency of a wave
This is the number of complete cycles of the wave passing a certain point per second
What is a period for waves
How long it takes for one full cycle
What are transverse waves
These are waves with perpendicular vibrations and are most waves. Examples are electromagnetic waves, s-waves and ripples in water
What are longitudinal waves
These are waves where the vibrations are parallel to the direction the wave travels. Examples are sound waves
Name 3 ways to measure waves
Oscilloscope’s can measure wave speed of sound, strobe lights can measure the wave speed of water ripples, peak frequency can measure wave speed in solids.
What are the equations for wave speed
Wave speed = distance / time
Wave speed = frequency * wavelength
What happens when a wave meets a boundary
It can be absorbed- which means the energy gets transferred to the materials energy stores
It can be transmitted- which means the wave carries on travelling through the object
And it can be reflected- this is where the wave is sent back by the object
What happens when a wave refracts at a boundary
This happens because a wave travels at different speeds in different densities. So when it goes at an angle this change in speed causes a change in direction.
What is ultrasound
A sound with frequencies higher than 20,000 Hz
What happens when ultrasound waves meet a boundary
These waves get partially reflected. This is because some waves get reflected and some refracted and transmitted.
What is ultrasound used for
Ultrasound is used for medical imaging and industrial imaging
What is infrasound
Sound with frequencies below 20Hz
What is the difference between p-waves and s-waves
P-waves are longitudinal, travel through solids and liquids, and are faster. S-waves are transverse and only travel through solids. These are slower
What is the equation for energy
Energy = force x distance
What is the equation for change in gravitational potential energy
Change in gpe = gravity x mass x change in height
What happens if the angle of incidence is large than the critical angle
The wave will experience internal reflection
What happens if you use a blue filter
All colours except for blue are absorbed
What happens if a red hat is looked at through a blue filter.
It would appear black as red light isn’t transmitted by the colour filter
Order the continuous spectrum by wave length
Radio waves, micro waves, infrared, visible light, ultraviolet, x-rays, gamma rays
What are each EM wave used for
Radio waves - communication and broadcasting and satellite , microwaves - satellites and microwaves, infrared - increase and monitor temperature, ultraviolet - fluorescent lamps, X-rays - let us look inside things (scans), gamma rays- sterilising things
What is beta-minus decay
It increases the chage of the nucleus. This changes a neutron into a protron and electron. Only atomic number increases by 1. Happens in a neutron rich nucleus
What is beta-plus decay
A proton is changed into a neutron and a positron. No change to mass number and atomic number decreases by 1. It is a proton rich nucleus.
What happens neutron decay
A nucleus emits a neutron. Mass number decreases by 1
What is the half life
It is an average time for half of the radioactive nuclei to decay
What does exposure to radiation do
It irradiates you
What does it mean for radioactive particle to get onto objects
This is contamination
What is nuclear fission
This is a chain reaction. Where a slow moving neutron is fired at a large unstable nucleus. Often uranium-235. That uranium then splits into 2 stable isotopes and produces 2 neutrons.
Why must chain reactions be controlled
This is because neutrons produced by fission have lots of energy. And in order to do fission they need to be slow moving. To do this fuel rods are placed in water. Then control rods limit the amount of fission by absorbing excess neutrons.
What is gamma decay
This is a way of removing excess energy from an atom. The nucleus goes from excited to more stable
What is nuclear fusion
This is where hydrogen-1 and hydrogen-2 fuse to make helium.
Why does nuclear fusion need to be at high temperatures and pressures
This is because the 2 isotopes will repel each other unless put under exreme pressure.
What are the 2 models of the solar system
Helio-centric and geo-centric
What is the steady state theory
It says the univers has always existed as it is now. As the universe expands it creates matter meaning it keeps the same density.
What does red shift suggest
The universe is expanding
What is red shift
Everything is moving away. So all waves get stretched. As they stretch wave lengths increases . So can no longer see so much purple but can see more red
What is the cycle of a star
Nebula, protostar, main sequence star, red giant, white star or supernova, neutron star or black hole.
What is the equation for work done
Work done = force x distance
What is the equation for power
Power = work done / time
What happens if an electron gets excited
It goes to an outer shell
What happens in an atom is ionised
It means it loses an electron
What is a stable nucleus
A nucleus with an equal amount of protons and neutrons
What is an alpha particle
Helium nuclei
What does alpha decay do
Decreases the charge and mass of the nucleus. When a nucleus emits and alpha particle it loses 2 proteins and neutrons. Mass number decreases by 4 and atomic number decreases by 2
