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|
Mechanics
Motion
|
Quantity |
Definition |
Vector/
Scalar
|
S.I. Unit |
|
Displacement |
distance moved in
a specified direction |
v |
m |
|
Speed |
distance moved per
unit time |
s |
ms-1 |
|
Velocity |
distance moved per
unit time in a specified direction |
v |
ms-1 |
|
Acceleration |
change in velocity
per unit time |
v |
ms-2 |
The
Equations of Motion
These equations
are useful for solving problems in which objects are moving
with uniform acceleration.
If the sense of
the motion changes, decide which sense is positive
before starting the calculations.
| t |
represents time |
| a |
represents acceleration |
| u |
represents "initial"
speed (or velocity) |
| v |
represents "final"
speed (or velocity) |
| s |
represents
the displacement from some
reference point (usually the starting
point) at time t.
If the reference point is not the starting
point, we might also see so in the
equations (where so means the displacement
at time t = 0). |
The equations
will give us the magnitude and sense
of the velocities, accelerations and displacements.
Displacement
against Time Graphs
|
 |
a)
stationary
b) uniform
velocity |
|
 |
| uniform
acceleration |
The slope of a s/t graph
represents velocity.
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© David
Hoult 2008 |