5
In a coordinate system we can plot the motion of a body. This is saying we draw a graph that shows us the position s as function of time t.

Start
the animation and notice that every second
the associated value of position s is measured.
The measurements of time and position belonging together is then plotted as points in a (t,s)graph. Please press the 'Reset'button and use the 'Step'functions and the mouse to check up on the measured points. By connecting these points, we find that the graph is a straight line. Now, determine the velocity of the skier. (Answer) 


6
We defined the velocity as
This expression has an important connection to the (t,s)graph for the motion as we shall see now.

Remake the
graph from the animation above.
As the graph is a straight line it makes sense to determine the slope a of the line by using the delta method. 

Comparing the two expressions we find that the slope of the line is equal to the skiers velocity. 
7
You can determine the velocity of a body by looking only at the (t,s)graph.

Show the graph of a body in motion and determine the velocity. (Answer) Click here to get some help. 

Move on to Motion  average velocity