P2- Physics Flashcards
What is acceleration ?
Is how quickly the velocity is changing speed or direction
What is the difference between weight and mass ?
Mass is the amount of stuff in an object weight is caused by the pull of the gravitational force mass is in kg weight is in Newtons
What is the resultant force ?
Is the overall force on a point or object it results in a change of velocity
What is stopping distance ?
The sum of thinking Distance and braking distance
What is thinking distance affected by ?
How fast you are going and how aware you are
What is braking distance affected by ?
How fast your going how good your brakes are how good the tyres are and how good the grip is
What is kinetic energy ?
Is energy of movement the more an object weighs and the faster it’s going the greater the kinetic energy
What is power ?
The rate of doing work
What is momentum ?
Property of moving objects the greater the mass and the greater it’s velocity the more momentum the object has
How does force affect momentum ?
A larger force means a faster change of momentum so a greater acceleration
What happens when u apply the brakes on a car ?
Work is done the brakes reduce the kinetic energy of the car and transfers it to heat energy
What is a build up of static caused by ?
Friction
What is the current ?
The flow of electrical charge round the circuit
What is potential difference ?
The driving force that pushes the current round
What is resistance ?
Anything in the circuit that slows the flow down resistance increase with temperature
What does an ammeter do ?
Measures the current must be placed in a series can be lit anywhere in the main circuit
What does a voltmeter do ?
Measures the potential difference across the component must be placed in parallel around the component
What happens to the current in a diode ?
The current only flows in one direction
What happens to the resistance of a thermistor we temperature increases ?
The resistance of the thermistor decreases
What happens in a series circuit?
Potential difference is shared , the current is the same everywhere, resistance adds up and the cell voltages add up
What happens in parallel circuits ?
The potential difference is the same , the current is shared
What is the uks main supply ?
230 volts
What did Rutherford discover from the plum pudding model ?
The nucleus must have a positive charge
Definition of alpha particles
Has two neutrons and two protons they are big and heavy so they don’t penetrate far into materials, because they are large they are strongly ionising
Definition of beta particles
Are electrons move quite fast and small penetrate moderately and have a long range in air
What are gamma rays ?
Very short wavelength EM waves they penetrate far into materials and pass straight through air they are weakly ionising and have no mass and no charge
What is half live ?
Is the average time it takes for the number of nuclei in a radioactive isotope to half
What is nuclear fission ?
The splitting up of big atomic nuclei a slow moving neutron is absorbed into a Uranium or plutonium nucleus this causes the Neuton to split which spits out another two or 3 neutrons the chain reaction then continues
What is nuclear fusion ?
The joining of small atomic nuclei only happens at very high temperatures
How does a protostar form?
Starts initially form from clouds of dust and gas gravity causes them to spiral forming a protostar
What happens after a protostar ?
Gravitation energy is converted to heat energy so temperature rises the hydrogen nuclei then undergo
Nuclear fusion to give out heat and light a start is then born
How does a main sequence star then form ?
Starts enter a long stable period due to masses of hydrogen
How does a red giant form ?
The hydrogen Begins to run out red giant forms and is red because the surface cools
