Physics P2 Flashcards
Physics (19 cards)
Newton’s First Law
An object remains stationary/ in motion at a constant speed in a straight line unless acted on by an unbalanced force
Newton’s Second Law
The acceleration of an object is proportional to the resultant force acting on it and inversely proportional to the object’s mass
Newton’s Third Law
When two objects interact, the forces they exert on each other are equal and opposite
Moment
The turning effect of a force
Upthrust
Is weight=upthrust the object floats
The upthrust is equal to the weight of the fluid that has been displaced
Displacement
Displacement is a vector of distance
Inertia
F=ma
Inertial mass is m
An object’s inertial mass measures how difficult it is to change the velocity of an object
Period
The amount of time it takes for a full cycle of the wave
Transverse
The oscillations are perpendicular to the direction of energy transfer
Motor Effect
Wire with current has a magnetic field and when it goes into another magnetic field between two poles, it experiences a force as the magnetic fields interact with it meaning the wire can move innit
Flemming’s stupid left hand rule
Thumb- Motion
First Finger- Field
Second Finger- Current
Motor dc
The split-ring commutator swaps the contacts every half turn to keep the motor rotating in the same direction
Loudspeaker motor effect
AC so current reverses so the force acts in the opposite direction so the cone moves in the opposite direction meaning it vibrates which causes changes in pressure so creates a sound wave
Generator effect
The induction of a p.d. in a wire which is moving relative to a magnetic field or experiencing a change in magnetic field
You can do this by moving a magnet in a coil of wire OR moving a conductor (wire) in a magnetic field “cutting” magnetic field lines
Alternator generator effect
Uses slip rings and brushes so contacts don’t swap every half term and it produces and ac current
Produces an induced ac
Dynamo generator effect
Uses split-ring commutator which swaps the connection every half turn to keep the current flowing in the same direction
Produces an induced dc
Microphone generator effect
Sound waves hit a flexible diaphragm attached to a coil of wire wrapped around a magnet. Coil moves in magnetic field which generates a current.
Converts pressure vibrations into vibrations in a current in an electric circuit.
Transformers type of current
A.C.
Step up transformers
Increase p.d.
Decrease current (less energy wasted heating wires and surroundings so it’s efficient)
More turns on secondary coil
