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karati so here we have one of our
calculations so we've been given a
question that says calculate takeoff
velocity of a 1.0 2 meter vertical jump
so first off we just start by
identifying the important information so
we are looking for the takeoff velocity
and we have a 1.0 2 meter vertical jump
okay so when we see vertical jump we can
remember that at the top of a vertical
jump our final velocity is always 0 so
at the top of a jump
our final velocity is always 0 we also
remember when we're in the air we are
being affected by gravity and so that is
going to be our acceleration and if you
remember gravity acting on us as it is
acceleration is negative 9.81 okay then
we can see that we also have a
displacement and in this case it is 1.0
2 meters and we are looking for our
takeoff or initial velocity all right so
we can then utilize our formula for
identifying uniformly accelerated motion
and that formula is V F squared is equal
to the I squared plus 2 times
acceleration times displacement so when
we
see a formula like that it means two
times acceleration times displacement so
we can write that out so VI squared plus
two times our acceleration times and
displacement okay so we can now fill in
from our key into our formula so VF is 0
we are trying to identify our initial
velocity plus 2 times negative 9.81
times 1.02
alright so 0 squared 0 still haven't
found our initial velocity and then we
calculate how formula here and that
works out to the negative 20 point 2 1
so negative 20 point oh one all right so
when we have a negative and a positive 3
times a negative and a positive we
always end up with a negative so we have
negative 20 point oh one okay so we now
need to try get our initial velocity on
its own and how we can do that is to add
20 point oh one on this side so we can
get rid of that there but whatever we do
on this side we have to do on the other
side of the equation so we then land up
with
zero plus twenty point zero one here
because we added twenty point oh one to
this side we have to add twenty point oh
one to that side okay it's still not
finished because on this side here we
have our initial velocity squared we
just want our initial velocity on its
own so to get rid of l squared we can do
a square root which leaves us with VI
and whatever we do on one side we have
to do on the other so we have the square
root of 20 okay so our answer is going
to be four four point four seven meters
per second and our direction is going to
be upwards
