Common assumptions made in modelling incl:
o No air resistance / wind
o The ground is level, flat, & smooth
Maths o The object is a particle (ie. the size is
Yr 1 Mechanics Ch 8 Summary ignored).
Modelling Vector quantity - has magnitude & direction.
Scalar quantity - has magnitude only
[8] On earth the value of gravity is 9.8m/s (downward
acceleration)
The units used for force are newtons (N) or Kgms-2
Newton's 1st law - an object moving @ a constant
velocity (incl @ rest) will continue to do so unless a
resultant force acts on it.
Newton's 2nd law - F=ma
Maths W = mg
Newton's 3rd law -for every action there is an equal
Yr 1 Mechanics Ch 10 Summary & opposite reaction
Forces & Motion Tension (t) acts towards the centre of the string
[9] The assumptions made for connected particles incl:
o Rope is light
o Rope is inextensible
In pulley questions it is assumed that the pulley is
smooth.
On a displacement (s) -time (t) graph, the gradient
represents the velocity (velocity = rate of change of
displacement).
On a velocity (v) - time (t) graph, the gradient is the
acceleration (rate of change of velocity).
Av speed / velocity =
Maths total distance /total displacement
Yr 1 Mechanics Ch 9 Summary total time taken
Constant Acceleration The area between the vt graph & the x-axis is the
distance travelled.
[9] v = u + at
u+v
s=( )t
2
v2 = u2 + 2as
s = ut + ½at2
s = vt + ½at2
o No air resistance / wind
o The ground is level, flat, & smooth
Maths o The object is a particle (ie. the size is
Yr 1 Mechanics Ch 8 Summary ignored).
Modelling Vector quantity - has magnitude & direction.
Scalar quantity - has magnitude only
[8] On earth the value of gravity is 9.8m/s (downward
acceleration)
The units used for force are newtons (N) or Kgms-2
Newton's 1st law - an object moving @ a constant
velocity (incl @ rest) will continue to do so unless a
resultant force acts on it.
Newton's 2nd law - F=ma
Maths W = mg
Newton's 3rd law -for every action there is an equal
Yr 1 Mechanics Ch 10 Summary & opposite reaction
Forces & Motion Tension (t) acts towards the centre of the string
[9] The assumptions made for connected particles incl:
o Rope is light
o Rope is inextensible
In pulley questions it is assumed that the pulley is
smooth.
On a displacement (s) -time (t) graph, the gradient
represents the velocity (velocity = rate of change of
displacement).
On a velocity (v) - time (t) graph, the gradient is the
acceleration (rate of change of velocity).
Av speed / velocity =
Maths total distance /total displacement
Yr 1 Mechanics Ch 9 Summary total time taken
Constant Acceleration The area between the vt graph & the x-axis is the
distance travelled.
[9] v = u + at
u+v
s=( )t
2
v2 = u2 + 2as
s = ut + ½at2
s = vt + ½at2
