## Statement

difficulty Given the following graphs that show the variation of the speed with time of three different bodies, answer the following questions: a) Which case has the fastest variation of the speed?
b) What does the slope represent in each one of the 3 cases?
c) Why is the line in case I horizontal?
d) In case I, does the possibility exist that the body is experiencing acceleration?

## Solution

a) If we observe the graphs, the stronger variation is case III. This is a variation that results in a fast decrease of the speed (the magnitude of the velocity vector).

b) The slope of the lines corresponds to the acceleration. The greater or smaller the acceleration, the steeper the increase or decrease of the speed.

c) Because the speed neither increase nor decrease.

d) Yes, even though a body does not experience a change in its speed, it is possible its velocity is changing direction. Which cannot be appreciated in the graphs.

We haven't found any remarkable formula in this exercise.