physics 2

• Ohm's Law states that the current flowing through a conductor is directly proportional to the voltage across it and inversely proportional to its resistance.
• work done = force x distance in a direction
• power = work done / time taken
• gpe = mass x field strength x height
• ke = 0.5 x mass x speed^2
• momentum = mass x velocity
• in the right hand rule, the thumb is the direction of current and the curled fingers the direction of magnetic field
• if the current is increased in an electromagnet, so will the magnet strength
• when a current flows through a coiled wire (solenoid) a magnetic field is created
• the solenoid magnetic lines are uniform and go in the same direction
• if you place iron in a solenoid, it creates an electromagnet and the field strength increases
• iron, cobalt and nickel are the elements that are used in magnets
• in flemmings left hand rule, the thumb is the direction of the force
• in flemmings left hand rule, the pointer finger represents the direction of magnet field n-s
• in flemmings left hand rule, the middle finger represents the direction of the current
• a transformer has two coils with different numbers of turns on them
• To change the direction of the magnetic field lines, you change the direction of the flow of current through the wire
• the magnetic field is transfered from the first coil to the second
• current is not passed in a transformer beause the core is an insulator
• the moment is the turning effect of a force
• moment = force x perpendicular distance
• levers make work easier because they increase the distance from the pivot
• gears transmit tourque
• specific heat capacity is the amount of energy required to heat 1kg of a substance up by 1 degree
• specific latent heat is the energy it takes to change the state of 1kg of a substance
• you can use a displacement can to find the volume of things
• during electromagnetic induction, the magnet moved relative to the wire causes a current to flow.
• changing the direction of the magnet in electromagnetic induction changes the current of the wire and induces a potential difference
• in a motor, the direction of the current through the coil means one side is pushed up and the other down. the metal ring is split so with every half turn the current in the coil changes direction bc the carbon brushes lose contact with the split ring. this ensures the force on the coil always turns in the same direction and it spins
• at a power station, step up transformers increase the potential difference and decrease the current