1.1 Physical Quantities and Units
Physical quantity is defined as a quantity which can be measured.
It can be categorized into 2 types
Basic (base) quantity
Derived quantity
Basic quantity is defined as a quantity which cannot be derived
from any physical quantities.
1.2 Scalars and Vectors
Scalar quantity is defined as a quantity with magnitude only.
e.g. mass, time, temperature, pressure, electric current,
work, energy and etc.
Mathematics operational : ordinary algebra
Vector quantity quantity is defined as a is defined as a quantity with both magnitude quantity with both magnitude
& direction.
e.g. displacement, velocity, acceleration, force, momentum,
electric field, magnetic field and etc.
Mathematics operational : vector algebra
CHAPTER 2:Kinematics of Linear Motion
straight line path.
Distance, d
-- the total length of travel in moving from one
location to another.
-- scalar quantity.
-- always positive.
Displacement, s
-- straight line distance from the initial
position to the final position of an object.
-- Vector quantity
-- can be positive, negative or zero
Speed, v
-- Rate of change in distance
-- S.I. unit : m s
–1 ; scalar quantity
Average Speed, ( v)
-- total distance traveled divided by the total
time elapsed in traveling that distance
Velocity, v
-- tells us how fast object is moving & in which
direction it is moving
-- is the rate of change in displacement.
-- vector quantity ;
SI unit : m s
–1
-- Deceleration : object is slowing down (direction
of acceleration is opposite to the direction of
the motion or velocity).
Average acceleration
-- change in velocity divided by the time taken
to make the change.
-- vector quantity.
-- SI unit : m s
From (1) : v = u + at , get an expression for t :
–2
rearranged to give:
v = u + a t… (1)
Distance traveled, s = area under the graph
= area of trapezium
s=1/2 (u+v)t… (2)
Substitute (1) into (2) :
s= (u+u+at )t
become
s = ut +1/2 at^2 … (3)
t=(v-u)/a
Substitute into (2) :
=(v+u)(v-u)/2a
2as=v^2-u^2
v^2 =u^2+ 2as … (4)
