Physical Science Paper I
Physics Study Notes
Rea’s Notes
Grade 12
2016
3 Hour Exam
200 Marks
Table of Contents
Kinematics (Motion in 1D) --------------------------------------------------------------------------------------------------- 1
Newton's Laws and Application of Newton's Laws ----------------------------------------------------------------------- 5
Momentum, Impulse, Work, Energy and Power -------------------------------------------------------------------------- 7
Gravitational and Electric Fields -------------------------------------------------------------------------------------------- 13
Electric Circuits ---------------------------------------------------------------------------------------------------------------- 16
Photons and Electrons -------------------------------------------------------------------------------------------------------- 20
PREFIXES COMMONLY USED FOR UNITS ------------------------------------------------------------------------- 26
italics = learn by heart
(*) definition formula
not on formula sheet
, Kinematics (Motion in 1D)
Vectors
scalar physical quantity, has magnitude only e.g. mass, energy
vector physical quantity, has magnitude & direction e.g. velocity, force
single vector which has same effect as original vectors acting
resultant vector
together
Resultant of perpendicular vectors
Head-to-tail method
1. draw first vector
2. draw second vector, tail joined to head of first
3. resultant from tail of first to head of second
Tail-to-tail method
1. draw first vector
2. draw second vector, tail joined to tail of first
heads pointing outwards
3. parallelogram drawn with vectors as sides
4. resultant from tails to opposite corner of parallelogram
Resolution of a vector into its components
when force acts at an angle to horizontal
can be divided into horizontal & vertical components
these have a sum equal to given force
general rule
horizontal / resultant x:
vertical / resultant y:
Displacement, Velocity and Acceleration
distance length of path travelled scalar, in m
displacement change in position vector, in m
speed (*) rate of change of distance -
scalar, in
velocity (*) rate of change of position / rate of displacement -
vector,
acceleration (*) rate of change of velocity -
vector,
instantaneous velocity at a particular time = slope of its position vs. time graph at that time
average velocity between two times = slope of line joining the two points on position vs. time graph
Rea’s Notes | Page 1
, Vertical Projectile Motion in One Dimension
(near the surface of the Earth in the absence of air resistance)
Free fall
free fall motion of a body in which only force acting on it is gravity (i.e. no air friction)
acceleration due to gravity on Earth is always - downward if air resistance is negligible
when an object is thrown vertically upward, its velocity at its highest point is zero
comes to rest momentarily before it changes direction and falls back
time up = time down
the speed at one point on way up is same as speed at same point on way down
Air Resistance
air resistance velocity of object
faster the object, greater the air resistance
also affected by area of object, e.g. parachute, larger, more air resistance
terminal constant velocity that free falling object reaches when air resistance prevents further acceleration
velocity net force = 0
Hot air balloon
hot air balloon already moving therefore
initial velocity of object = vector sum of velocity of balloon and velocity at which object was released
Rea’s Notes | Page 2
Physics Study Notes
Rea’s Notes
Grade 12
2016
3 Hour Exam
200 Marks
Table of Contents
Kinematics (Motion in 1D) --------------------------------------------------------------------------------------------------- 1
Newton's Laws and Application of Newton's Laws ----------------------------------------------------------------------- 5
Momentum, Impulse, Work, Energy and Power -------------------------------------------------------------------------- 7
Gravitational and Electric Fields -------------------------------------------------------------------------------------------- 13
Electric Circuits ---------------------------------------------------------------------------------------------------------------- 16
Photons and Electrons -------------------------------------------------------------------------------------------------------- 20
PREFIXES COMMONLY USED FOR UNITS ------------------------------------------------------------------------- 26
italics = learn by heart
(*) definition formula
not on formula sheet
, Kinematics (Motion in 1D)
Vectors
scalar physical quantity, has magnitude only e.g. mass, energy
vector physical quantity, has magnitude & direction e.g. velocity, force
single vector which has same effect as original vectors acting
resultant vector
together
Resultant of perpendicular vectors
Head-to-tail method
1. draw first vector
2. draw second vector, tail joined to head of first
3. resultant from tail of first to head of second
Tail-to-tail method
1. draw first vector
2. draw second vector, tail joined to tail of first
heads pointing outwards
3. parallelogram drawn with vectors as sides
4. resultant from tails to opposite corner of parallelogram
Resolution of a vector into its components
when force acts at an angle to horizontal
can be divided into horizontal & vertical components
these have a sum equal to given force
general rule
horizontal / resultant x:
vertical / resultant y:
Displacement, Velocity and Acceleration
distance length of path travelled scalar, in m
displacement change in position vector, in m
speed (*) rate of change of distance -
scalar, in
velocity (*) rate of change of position / rate of displacement -
vector,
acceleration (*) rate of change of velocity -
vector,
instantaneous velocity at a particular time = slope of its position vs. time graph at that time
average velocity between two times = slope of line joining the two points on position vs. time graph
Rea’s Notes | Page 1
, Vertical Projectile Motion in One Dimension
(near the surface of the Earth in the absence of air resistance)
Free fall
free fall motion of a body in which only force acting on it is gravity (i.e. no air friction)
acceleration due to gravity on Earth is always - downward if air resistance is negligible
when an object is thrown vertically upward, its velocity at its highest point is zero
comes to rest momentarily before it changes direction and falls back
time up = time down
the speed at one point on way up is same as speed at same point on way down
Air Resistance
air resistance velocity of object
faster the object, greater the air resistance
also affected by area of object, e.g. parachute, larger, more air resistance
terminal constant velocity that free falling object reaches when air resistance prevents further acceleration
velocity net force = 0
Hot air balloon
hot air balloon already moving therefore
initial velocity of object = vector sum of velocity of balloon and velocity at which object was released
Rea’s Notes | Page 2
