okay hi guys um this is going to be a small recap of all the equations in ihcc physics for board exams in 2023 and this includes space physics which is an addition from last year's syllabus all right let's get started first off we have motion equations of motion so first we have velocity which is nothing but displacement by time one thing you note is that displacement is a vector quantity and speed is a scalar quantity and speed is equal to Distance by time while the velocity is equal to displacement by time so using that simple logic we get that velocity is a displacement is a vector quantity while speed is a scalar quantity average velocity is equally the total displacement by The Tool Time and the more commonly used one would be the average speed which is equal total distance by total time all right and a is equal to V minus U by T that's a pretty simple equation it's nothing but the rate at which velocity changes and rate basically brings in the idea of time and mathematically speaking acceleration is the derivative of velocity in respect to time and velocity is the derivative of displacement in respective time and therefore acceleration is nothing but the second derivative of displacement in respect to time that is just mathematically speaking then you have these two simple equations where digital Mass into gravity and four signal mass and acceleration and from this by simply comparing those two equations we see that mass is constant but a is equal to G and F is equal to W which basically implies that weight is the force acting on an object when the only um is weight is the force and object experiences when gravity is the only accelerating force acting on it and the value for gravity on Earth as accelerating force is 9.81 meters per second squared while the field strength of the earth is 9.81 Newtons per kg these are some further motion equations which are not necessary for us in IGCSE but these can be helpful I like to call these the suvat equations SUV a t where s is displacement initial velocity final velocity acceleration and time and if you notice these four are vector quantities and this is a is a scalar quantity all right this will come in handy next year in a levels when you will actually have to uh so if you have something like this launching it like this this is Theta you have to you have to separate this Force into its Vector quantities so this will be cos Theta sine Theta right that is why these will come in handy because all of them will have an X and Y component while time will only be a scalar quantity and these are just the equations for them which we don't need to go in depth for then you have density moment forces and pressure this is density mass by volume and it is measured in kg per meter cubed pressure is equal to force by area so it's measured in Newtons per meter squared and 1 Newton per meter squared is equal to one pascal and in liquids it is equal to rho GH density into gravity to height and this gravity is a field strength 9.81 Newtons per kg force is equal to K Delta X which is hooke's law case has been constant Delta X is the displacement of the spring and force is the force in the spring Force um D spring is observing and the moment of force will perpendicular distance into Force applied and it is measured in newton meters momentum is equal to mass inter velocity and it is measured in kg meters per second and we later get to know that that is the same thing as one Newton Second we can do the derivation in the later slide in an isolated system momentum initially is equal to the final momentum and in an isolated system there is no exchange of matter and there is no exchange of energy either with the surroundings in a closed system there is exchange of energy but there is no exchange of matter and in an open system there is an exchange of energy and matter so when it's an isolated system which is what we will be under the assumption of in IDC physics there will be the conservation of momentum meaning that the final initial and final and initial momentum will be the same then we have forces in equilibrium where the opposite forces will basically counter each other being there are to be of the same magnitude but in the opposite direction and this is where we get the idea of force in terms of momentum so simply deriving this we get f is equal to M A that's Newton's Second Law acceleration is nothing but V minus U by time taken which can then be written as MV minus mu divided by T which is nothing but Delta P by T so we get force is equal to the change in momentum per unit time or by the time taken and therefore we get one more unit which is impulse f t is equal to Delta p this is where sorry this is where we get uh the idea that impulse is uh nothing but Newtons into seconds right so one Newton Second um yeah this is Newton's second okay this is measured in Newton seconds and this is measure in kilogram meters per second and they're the same thing basically now energy work done is nothing but energy and is the same thing is measured in joules and this is nothing but force in a distance or and in related classes you'll get cosine Theta involved which will make sure that it's only perpendicular distance so basically as work done is a is a scalar quantity we can use distance instead of displacement so in the later classes we'll get work done is equal to force into distance into cosine Theta which will be angle to make sure that it's only the horizontal perpendicular distance that you're making sure of dynamic Counting then you have Clinic energy equal to MB squared by two percent energy is a gravitational potential energy which is equal to MGH and elastic potential energy is equal to K Delta x square divided by two Delta X is again the displacement K is the spring constant divided by two and an isolate system energy is conserved that's the idea right if you go back we see that in isolated system energy is conserved and it's the only system that energy is conserved and that is why it's only in the isolated system and what happens is that as kinetic energy gains there's a gain organic energy potential energy decreases as a potential energy increases can energy decreases and a very good example of that would be something like a pendulum so if you have something like this this is a pendulum this is a pendulum it has its maximum speed um right about here this is V Max V Max means that it's kind of kinetic energy is maximum kinetic energy is Max right simple logic goes MV squared by two maximum over here potential energy is Max which means that kinetic energy zero and over here we have but it kind of going to be Mark which means that potential energy is zero simple conversion like I said um rate at which energy is transferred already work is done it's nothing but Power it is measured in joules per second or Watts family physics we have e is equal to ml and the conversion between Kelvin and degree celsius this value over here zero Kelvin is absolute zero and that's it is grammar L is latent heat and latent heat of linear heat in general is the energy needed to change the state of a unit Mass um by from let's say liquid to solid sorry solid to liquid that will be Fusion and the radiative vaporization will be from liquid to gas that's it see in this case is specific heat capacity which is nothing but the energy needs to increase the temperature for substance by one degree Celsius when it has a weight of 1 kg and a faster or a better way to say this would be the energy change um needed to increase the temperature for unit mass by 1 degree Celsius or even one Kelvin because the conversion between them if you have one Kelvin and one one Kelvin is going to be equal to what minus 272 degrees Celsius so what we see the change between them is one so therefore one Kelvin is equal to one degree Celsius when it comes to conversion between them they are not but an increment of one Kelvin is equal to an increment in one degree Celsius this is what I mean by that previously well you don't have this equation in icjc but this basically shows us that pressure is directly proportional to temperature pressure volume is directly pushed into temperature but pressure and volume are inversely proportional to each other n is the number of moles R is the molar gas constant so this is just two constants that we don't care about right now then you have waves where we have B is graph Lambda V is velocity f is frequency and Lambda is wavelength frequency is measured in one by a second or second to the bar minus one or Hertz when it comes to reflection we have sine I is equal to sine r or simply the angle of incidence is equal to angular reflection that's it refraction index or it should be refractive index over here is nothing but the refractive index of the first medium uh multiplied with this angle of incidence sine of the angle of incidence N2 is this IR refractive index of the second medium multiplied with sine arms of the refraction angles of a fraction and therefore with this if with this we can get the idea that sine I by sine r is equal to what into Pi N1 if you use this logic then if N1 is air mean that the initial medium was air we can get the idea that it has a refractive and X of zero so we just cancel this out the refractive index of a medium and light is traveling from Air to the second medium is equal to sine I by signal this is Snell's law then you have n is equal to 1 by sine c c is the critical angle which is the angle of incidence at which the incident wave or the incident wave basically gets refracted perpendicular to the normal and there's some form of refract of a total internal reflection also taking place and then you have energy we'll see why we were in this case C is the speed of light in vacuum which is three times and above 8 meters per second and V is the speed of light in that specific medium then I have a molecule here for the electromagnetic spectrum which I used which is real monkeys interest very useful Xmas gifts and this visible light over here that we see if you remember if you notice infrared means well there's red hidden over here which means that when you start writing bibbed cure or the opposite of what you me of whatever it is red is windy on the top and why that is going to be on the top on the bottom because ultra violet right so that is one way to remember it and another thing is that in this order is of increasing frequency as you go down it's increasing frequency increasing energy but decreasing wavelength energy and frequency are directly proportional to each other then you have electricity and magnetism charge is equal to the current into time and therefore current is equal charge by time resistance is equal to voltage by current power is equal to current into voltage energy is equal to current into voltage into time because energy is nothing but Power into time and potential difference and electric potential basically voltage is equal to work done by a charge quantity which basically means joules per coulomb if you have a Transformer over here and a transform over here there will be turns on both of them right the number of turns is normally not equal because that's only only then will there be actual use of a transformer basically the voltage the ratio of the voltage between these two is equal to the ratio of the interns between them and the power between them is conserved however if it's a stop Step up Transformer then there'll be more turns on this meaning that the voltage on this will be greater meaning that the current on this will be lower and if it step down then the voltage on this will be lower current on this will be higher one thing to know is that as uh if it's the Step up Transformer that means that the voltage is higher current is lower as the current is lower there'll be a lower temperature of the wire the temperature or the buyer will be at a lower temperature which means that there'll be greater uh conductivity or lower resistivity and lower resistivity means that there will be a greater efficiency of transfer of energy not as violence over a long distance you use a Step up Transformer on one side to basically increase the efficiency of the transfer of energy then you have nuclear physics which basically starts off with basic chemistry we have protons neutrons and electrons charge of one zero one minus retrospectively at a mass of one AMU 1 mu and one by one eight four zero Amu one important thing well not important but one very interesting thing is that protons and neutrons are actually not fundamental particles they are made up of quarks up cook and down cook and if you want to research on that further I'll let you know that a proton is made up of two up quarks and one down quote while a neutron is made of one up quark and two down quarks electrons fall under the field of leptons then you have the Decay um firstly are the particles of the particle beta particles in normal radiation gamma radiation is nothing but the gamma waves from the electronic Spectrum so they have a charge of zero speed of light mass of zero and they have no ionizing effect but are very very very penetrating they have the highest magnetic effect of these two of these three particles alpha particles are basically the helium nuclei they have a speed of 0.07 C so the slowest of them all and they have a charge of two plus because they're a helium nuclei mass of four atomic mass units because they have two protons and two neutrons that are very ironizing but have a very low penetrating ability beta particles have a charge of minus one and are basically electrons they have a speed of 0.6 to 0.7 C they have a mass of this mass and our have a low analyzing effect but a higher penetrating ability than alpha particles then you have the nuclear Decay equations basically an alpha DK we have the emission of a helium nuclei and so you'll have to subtract 4 from the mass number and two from the atomic number then you have gamma dkv this asterisk over here basically symbolizes the presence of the element in its excited state and it's going to make the gamma radiation to get lost to lose that extra energy that it has and then you have beta decay in which a neutron gets converted into an electron and proton and so the mass number stays constant but atomic number increases and this is basically the General equation but note that there are two types would be the DK this beta positive D can be the negative Decay don't need to go any depth about that just remember this equation over here now we have space physics which is the addition and we have the average orbital speed which is nothing but 2 pi r by T and 1 by T which is one by time period is nothing but 2 pi RF uh it's going to be a frequency 1 by T is equal to frequency and 1 by f is equal to T then you have the Hubble constant H Sub 0 which is the ratio between this period which the the Galaxy is moving away from the earth and the distance from the earth and it has a value of 2.2 times about minus 18 seconds and well this equation over here if you reciprocate it then you get this equation over here which can have its own uses and well that's it thank you for watching