2471044
Description
Flashcards by Lauren Crawford, updated more than 1 year ago
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Created by Lauren Crawford
over 9 years ago
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| Question | Answer |
| Whenever two objects interact, the forces they exert on each other are... | equal and opposite |
| What is the resultant force? | The combined effect of the forces acting on an object |
| If the resultant force acting on a stationary object is zero, the object will... | If the resultant force acting on a stationary object is zero, the object will remain stationary |
| If the resultant force acting on a stationary object is not zero, the object will.... | If the resultant force acting on a stationary object is not zero, the object will accelerate in the direction of the resultant force |
| If the resultant force acting on a moving object is zero, the object will.... | If the resultant force acting on a moving object is zero, the object will continue to move at the same speed and in the same direction |
| If the resultant force on a moving object is not zero, the object will... | If the resultant force acting on a moving object is not zero, the object will accelerate in the direction of the resultant force |
| What two factors determine the acceleration of an object? | 1. The resultant force acting on the object 2. The mass of the object |
| What does the gradient of a distance-time graph represent? | Speed |
| What is velocity? | Speed in a given direction |
| What is the equation to find the acceleration of an object? | a=(v-u)/t v = final velocity u = initial velocity t = time |
| What does the gradient of a velocity-time graph represent? | Acceleration |
| What is stopping distance the sum of? | The thinking distance and braking distance |
| What can affect your thinking distance? | The speed you're travelling at and Tiredness/drugs/alcohol |
| When the brakes of a vehicle are applied, work done by the friction force between the brakes and the wheel ______ the kinetic energy of the vehicle and the temp of the brakes ______ | When the brakes of a vehicle are applied, work done by the friction force between the brakes and the wheel reduces the kinetic energy of the vehicle and the temp of the brakes increases |
| What can affect braking distance? | Your speed How good your brakes are How good the tyres are Weather conditions |
| What is thinking distance? | The distance the vehicle travels during the driver's reaction time |
| What is braking distance? | The distance the car travels under the breaking force |
| A force applied to an elastic object will result in the object ________ and storing _______ energy | A force applied to an elastic object will result in the object stretching and storing elastic potential energy |
| The extension of an elastic object is ________ to the force applied | The extension of an elastic object is DIRECTLY PROPORTIONAL to the force applied |
| What is the equation to work out the work done? | Work done = force x distance moved |
| What is transferred when work is done? | Energy |
| What is power? | The work done or energy transferred in a given time P=E/t |
| What is gravitational potential energy? | It is the energy of an object due to its position in a gravitational field |
| The kinetic energy of an object depends on what? | Its mass Its speed |
| What is momentum? | A property of moving objects |
| What is conservation of momentum? | In a closed system, the total momentum before an event is equal to the total momentum after the event |
| The build-up of static is caused by what? | Friction |
| When certain insulating materials are rubbed together they become what? | Electrically charged |
| ______ charged electrons are rubbed off one material and onto the other | Negatively |
| The material that gains electrons becomes _________ charged | Negatively |
| The material that loses electrons is left with what? | An equal positive charge |
| Two objects of the same charge ______ and two objects of different charge _________ | Repel Attract |
| What is electrical current? | A flow of electric charge |
| What is the size of the electric current? | The rate of flow of electric charge |
| What is the potential difference? | The work done per coulomb of charge that passes between the points |
| The resistance of a component can be found by measuring the ________ through and the ___________ across the component | The resistance of a component can be found by measuring the current through and the potential difference across the component |
| The current through a resistor is ______________ to the potential difference across the resistor | Directly proportional |
| What equation is used to calculate the current, potential difference or resistance? | V = I x R |
| The greater the resistance the _________ the current for a given potential difference across the component | The greater the resistance the smaller the current for a given potential difference across the component |
| For components connected in series the total resistance is what? | The total resistance is the sum of the resistance of each component |
| For components in series, is the current shared or is it the same everywhere? | The current is the same everywhere |
| For components in series, the total potential difference is what? | The total potential difference is shared between the components |
| For components connected in parallel, the potential difference is what? | The potential difference is the same |
| For components connected in parallel, the total current is what? | The total current is the sum of the currents through the separate components |
| The resistance of a filament bulb increases as the temperature of the filament __________ | The resistance of a filament bulb increases as the temperature of the filament increases |
| Through a diode, the current can flow..... | ....in one direction only |
| Why can the current only flow in one direction through a diode? | The diode has a very high resistance in the reverse direction |
| An LED emits light when a current flows through it in the ______ direction | An LED emits light when a current flows through it in the forward direction |
| As light intensity increases, the resistance of a LDR ________ | As light intensity increases, the resistance of a LDR decreases |
| What does LDR stand for? | Light-Dependent Resistor |
| What is D.C.? | Direct current. Batteries and cells supply current that always passes in the same direction |
| As the temperature increases, the resistance of a thermistor ________ | As the temperature increases, the resistance of a thermistor decrease |
| What is A.C.? | Alternating current. Mains current is constantly changing direction |
| In the UK, what is the frequency of mains electricity? | 50 cycles per second (50 hertz) |
| In the UK, what is the voltage of mains electricity? | 230 V |
| In a plug, what colour is the live wire and where is it positioned? | Brown and on the right hand side |
| In a plug, what colour is the earth wire and where is it positioned? | Green and yellow and in the middle |
| In a plug, what colour is the neutral wire and where is it positioned? | Blue and on the left hand side |
| What happens if an electrical faults causes too great a current? | The circuit is broken by a fuse or a circuit breaker in the live wire |
| What happens if the current in a fuse wire exceeds the rating of the fuse? | The fuse will melt, breaking circuit |
| What is an RCCB and how does it work? | Residual Current Circuit Breaker Operate by detecting a difference in the current between the live and neutral wires |
| Advantages of an RCCB? | Work much faster -> safer Notice small current changes that may not be enough to melt a fuse -> more effective against electrocution |
| Appliances with metal cases are usually what? | Appliances with metal cases are usually earthed |
| What is meant by "earthing"? | It means that the case must be attached to an earth wire |
| Why wouldn't an appliance be earthed? | Because it is double insulated meaning it has a plastic casing and no metal parts are showing |
| What happens when an electrical charge flows through a resistor? | The resistor gets hot |
| The rate at which energy is transferred by an appliance is called _______ | The rate at which energy is transferred by an appliance is called power |
| Power, potential difference and current are related by which equation? | P = I X V |
| Energy transferred, potential difference and charge are related by which equation? | E = V x Q |
| Why are some substances said to be radioactive? | Because they give out radiation from the nuclei of their atoms all the time |
| What is an alpha particle made of? | 2 protons and 2 neutrons |
| What is a beta particle made up of? | An electron |
| What is gamma radiation? | An electromagnetic wave |
| Alpha particles are deflected _____ than beta particles and in an opposite direction | Alpha particles are deflected less than beta particles and in an opposite direction |
| What is the relative ionising power of: a) an alpha particle b) a beta particle c) a gamma wave | a) alpha - high b) beta - medium c) gamma - low |
| What will absorb: a) an alpha particle b) a beta particle c) a gamma wave | a) alpha - tissue/paper b) beta - a few mm of aluminium c) gamma - nothing but lead absorbs quite a lot |
| What is the range of the following in air? a) an alpha particle b) a beta particle c) a gamma wave | a) alpha - 3-5cm b) beta - about a metre c) gamma - ∞ |
| Which types of radioactivity are deflected by electric and magnetic fields? | Alpha and beta are deflected but gamma is not |
| What is the half-life of a radioactive isotope? | The average time it takes for the number of nuclei of the isotope in a sample to halve |
| What two fissionable substances are in common use in nuclear reactors? | Uranium-235 and Plutonium-239 |
| What is nuclear fission? | The splitting of an atomic nucleus |
| For fission to occur, the uranium-235 or plutonium-239 must first what? | They must first absorb a neutron |
| The nucleus undergoing fission splits into two smaller ______ and two or three _______ and ______ is released | The nucleus undergoing fission splits into two smaller nuclei and two or three neutrons and energy is released |
| What is nuclear fusion? | The joining of two atomic nuclei to form a larger one |
| How are stars formed? | When there's enough dust and gas from space, it's pulled together by gravitational attraction |
| Why, suring the 'main sequence' period of its life, is a star stable? | Because the forces within it are balanced |
| Fusion processes in stars produce what? | All of the naturally occurring elements |
| The Sun is a main sequence star. Why will it eventually become a red giant, rather than a red super giant? | It does not have enough mass |
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