last minute exam revision Flashcards
what is current?
the electric charge transferred per unit time
give an example of a d.c supply
a battery
mains electricity?
50Hz
230 v
a.c
what is mass?
The amount of matter and object takes up
what is gravitational field strength?
The force due to gravity per unit mass
satellites have a constant vertical acceleration
force is a vector
Electrostatic charge has many applications in everyday life.
Using your knowledge of physics, discuss some of these applications
Cling film to keep food fresh
Static dusters for cleaning
Printers/photocopiers where charge attracts ink to the paper.
what do field lines show and where are they the strongest?
field lines in an electric field show the direction a positive charge placed in a field would make.
Field is strongest where field lines are closest together
order of particles in increasing size?
helium nucleus, electron, proton?
electron, proton, helium nucleus
how is something connected?
series or parallel
why is the …. not as fast as calculated in part …?
because energy is lost as heat due to friction
if given a forward force and a frictional force take away to get the force
who should you use a space based telescope instead of a ground based telescope?
no light pollution
can use it during the day
time for equivalent dose rate is just in hours/mins
what is acceleration?
acceleration is the change in velocity, per unit time
projectiles
A projectile is an object in unpowered flight. Ignoring air resistance there is only one force acting on a projectile - weight.
A projectile has:
A constant horizontal velocity
A constant vertical acceleration
parabolic flight path
projectiles 2
ONLY AIR RESISTANCE affects the time and object takes to fall, NOT MASS
a larger horizontal velocity will increase the horizontal range of the projectile, but doesn’t affect the time taken to fall.
As altitude increases, what happens to the acceleration of a rocket?
Acceleration increases because it’s weight decreases because fuel is burned & parts are ejected
As altitude increases what happens to the weight of a rocket?
As altitude increases weight decreases because gravitational field strength decreases as altitude increases and mass decreased because fuel is burned
w = mg
when doing resultant vectors do Pythagoras and it’s just the number WITH m UNIT
then when you do trigonometry ADD A DIRECTION
direction might be right, left, forwards, backwards
LOOK AT THE LITTLE ARROW AND SEE IF IT SAYS NORTH OR FORWARDS
what is weight?
The downwards pull on an object due to gravity
