00:02
So an example of kinematics in one dimension.
00:06
So there are a number of equations that you use when there is a constant acceleration.
00:15
And many of them involve time, or several of them, i should say.
00:21
And one of these tells us how far an object goes, delta x, given some initial velocity times time, and then plus one half a t -s.
00:35
Squared and of course we'll just say plus but if the acceleration is negative of course that can come in as a negative sign the other kinematic relationship involves the definition of acceleration that it is a change in velocity or speed really just velocity in time so a final velocity is equal to initial velocity plus the acceleration times time.
01:10
And again, that plus could be negative.
01:14
And we'll see a situation where this is true.
01:17
But notice that these involve time.
01:21
There is one kinematics equation that does not involve time.
01:27
And actually, this equation comes from energy conservation.
01:32
But it has the difference in squared and squares between velocity, final, squared minus initial velocity squared.
01:41
And this is twice times the acceleration, times the distance covered by the object.
01:51
And the left -hand side is related to the kinetic energy of the object.
01:56
The other side is related to the work that an object has done on it.
02:03
So here we're taking a look at an example of a spacecraft approaching a space station, for example.
02:15
And we are told the initial speed of the spacecraft and how far it has to go before it gets to the place where it's going to dock onto the spaceship.
02:27
And the spacecraft must decelerate...