23-08-2013, 04:30 PM
Deriving the equations of motion
Deriving the equations .pdf (Size: 41.84 KB / Downloads: 181)
Before we start to derive the equations of motion, it is important to
make sure we know the standard symbols for describing the
movement of an object. Conventionally, we use the following
symbols to represent the properties of an object.
Now let’s imagine an object travelling with velocity u ms-1.
If our object experiences an unbalanced force, this will cause the
object to accelerate at a ms-2. The force acts for a time t and so
the acceleration must also last for time t.
After t seconds, the object has final velocity v ms-1.
We will use both of the equations we have obtained so far to reach
the third equation of motion. This will require a bit of algebra so I
will only make small changes in each line so you can see what is
happening
Notice that both
s = ut + 1⁄2at2
and
v = u + at
include the time variable t.
There will be some situations when we do not have any information
about time and so it would be a good idea to derive an equation
that does not have a t term.