mass is the measure
of how much matter
an object has- weight
is the measure of how
strongly gravity pulls
on that matter
forces
when a force moves
an object through a
distance energy is
tranferred and work
is done
Work Done = Force x Distance
Gravitational potential energy= mass x g x height
Power = work done (or energy transferred)/ Time taken
Momentum (kg m/s) = Mass(kg) x Velocity (m/s)
Resultant force
a stationary objects
resultant force is zero
If the resultant force on a
moving object is zero the
object will continue to move
in the same direction at the
same speed
F= ma
m=mass (kg)
a= acceleration
(m/s)
F=resultant
force in
newtons
When two object interact
the forces they exert on
each other are equal and
opposite
Resistance
resistance- from fluid (air or liquid)
reduce resistance by making object streamline
increases as speed increases
Friction
friction - opposite direction to movement
Cars
things that affect stopping
distance: speed of vehicle,
thinking distance, weather
new car design
brakes - rather then converting
the kinetic energy of the vechicl
to heat enegry, brakes put
vechiles motor into reverse-
motor goes backwards wheels
slow down - electric generator
then stores this energy
Cars designed to
convert kinetic
energy safely in a
crash
by increasing time
over which
momentum changes
happen to lesson
forces on passenger
Crumple zones
Air bags
side impact bars
two different
parts of overall
stopping
distance of a
car- thinking
distance and
braking
distance
Terminal velocity
Atomic structure
Plum pudding
Isotopes- same
number of
protons but
different number
of neutrons
most isotopes are
radioactive, which
means they decay
into other elements
and give out
radiation
Types of radiation
alpha
slow moving , big ,ionising
helium- 2 neutrons, two protons
beta
quite fast, moderately ionising, simply an electron- charge of -1
gamma
penetrate far into materials, no mass or charge , weakly ionising
Electricity
Static electricity
caused by friction
insultating materials
result of a imbalance between
positve and negative charges in
an object. Build up on surface
of a object and find a way to be
released
rubbing certain materials against one
another can transfer negative
charges, or electons
only electons move- negative charges!
opposites repel
Charges attract
current- flow of electricity
Resistnace- anything in circuit
which slows the flow down
resistance increases with temperature
due to some electical energy transferred to heat energy
ammeter measures current
voltmeter measure potential differnce
types of circuits
series-
All of nothing
parellel
independance and isolation
Difference in speed
and velocity - velocity
involves speed and
idrection