# GCSE AQA Physics Unit 2 Flashcards

### Description

Flashcards on the specification of Physics unit 2
Flashcards by Gabi Germain, updated more than 1 year ago
 Created by Gabi Germain almost 9 years ago
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## Resource summary

 Question Answer What does the gradient of a distance-time graph represent? speed What is velocity? Speed in a given direction What does the gradient of a velocity-time graph represent? Acceleration How do you work out the distance travelled? The area underneath a velocity-time graph What is newtons third law? Every action has an equal and opposite reaction What is the resultant force? The combined effect of all forces acting on an object What does the resultant force acting on an object make it do? Changes its state of rest or motion What happens if the resultant force acting on an object is zero? It is stationary If the resultant force is not zero what will happen to the object? The object will accelerate in the direction of the resultant force If the resultant force acting on a moving object is zero what happens to the object? The object will continue to move at the same speed in the same direction If the resultant force acting on a moving object is not zero what will happen to ? The object will accelerate in the direction of the resultant force What is the acceleration of an object determined by? The resultant force acting on the object and the mass of the object When a vehicle travels at a steady speed the what balances the driving force? The resistive forces The greater the speed of a vehicle the ______ the braking force needed to stop Greater/Higher What is the stopping distance? Thinking distance + braking distance What is thinking distance? The distance the vehicle travels during the driver's reaction time What are three things that effect a drivers reaction time? tiredness, alcohols and drugs What happens when the brakes of a vehicle are applied? Work done by the friction force between the brakes and the wheel reduces kinetic energy of the vehicle and the temperature of the brakes increase How is the braking distance of a vehicle effected? weather conditions, brake condition and road condition The faster an object moves through a lfluid the________ the _________ that acts on it greater, frictional force Why will an object accelerating through a liquid initially accelerate? Due to the force of gravity, What is terminal velocity? When the resultant force is zero, drag force is equal to force making it move What may cause an object to change its shape? a force acting on the object What will happen when a force is applied to an elastic object? the object will stretch and store elastic potential energy e.g. spring What is Hooke's law? The extension of a spring is directly proportional to the force applied provided the limit of proportionality is not exceeded What is transferred when work is done? Energy What is the conservation of momentum? In a closed system the total momentum before an event is equal to the total momentum after the event What happens when certain insulating materials are rubbed together? They become electrically charged What are rubbed off from on material to another? Negatively charged electrons What happens when two electrically charged objects are brought together? They exert a force on each other (repel or attract) Diode Fuse Variable resistor Thermistor What is this graph for? For a resistor at a constant temperature What are current-potential difference graphs used to show? How the current through a component varies with the potential difference across it The current through a resistor is directly proportional to what? The potential difference across the resistor The greater the resistance the _______ the current Smaller What is the same across each component in series? The current What is the same in each component of a parallel circuit? Potential difference What does this graph show? The resistance of a filament bulb increases as the temperature of the filament bulb increases What does this graph show? The current through a diode goes in one direction and has a very high resistance in the reverse direction When does an LED emit light? When current flows through it in the forward direction When does the resistance of an LDR decrease? As light intensity increases When does the resistance of a thermistor decrease? As the temperature increases What is an alternating current? A current that is repeatedly changing direction What is direct current? Current that passes in only one direction In the UK what is the frequency of mains electricity? 50Hz and is about 230V What are the three wires in a three pin plug and what colour are they? Live wire (brown), neutral wire (blue) ant the Earth wire (yellow and green stripes) What is an RCCB? Residual Current Circuit Breaker What does the fuse do in a plug when the current exceeds the rating? It melts which breaks the circuit Which appliances usually have an earth wire? Ones with metal casing What happens when an electric charge flows through a resistor? It gets hot What is the basic structure of an atom? Protons, neutrons (nucleus) and electrons What is the relative mass of an electron? 0.0005 What is the relative mass of a proton or a neutron? 1 What is the relative charge of an electron? -1 Does an atom have an overall charge? No How do atoms become ions? By losing or gaining electrons? What is an isotope? The atom of an element with the same number of protons but different numbers of neutrons Why is a substance said to be radioactive? substances that give out radiation from their nuclei of the atoms all the time What do alpha particles have in their nucleus? 2 neutrons and 2 protons What does this represent? Beta decay

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