Answer:
Well, I think you're talking about kinematics, especially uniform rectilinear motion. We know that there is a specific equation for that:
S = Vt + S0
With S being the distance, V the velocity, t the time and S0 the initial distance (initial displacement).
From this you can calculate t, if that's what you want.
Centre of Mass then axis of rotation and then moment of inertia. This was the toughest question for your level... happy to help ^_^. It was purely experimental question.
Answer:
20 meters.
Explanation:
In the graph, the x-axis (the horizontal axis) represents the time, while the y-axis (the vertical axis) represents the distance.
If we want to find the distance covered in the first T seconds, you need to find the value T in the horizontal axis.
Once you find it, we draw a vertical line, in the point where this vertical line touches the graph, we now draw a horizontal line. This horizontal line will intersect the y-axis in a given value. That value is the total distance travelled by the time T.
In this case, we want to find the total distance that David ran in the first 4 seconds.
Then we need to find the value 4 seconds in the horizontal axis. Now we perform the above steps, and we will find that the correspondent y-value is 20.
This means that in the first 4 seconds, David ran a distance of 20 meters.