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3.1 Example 1

A car start from the rest with an acceleration of 3 m/s2. Which velocity, in km/h, have after 7 seconds? Which is the travelled distance in meters?

Solution with FisicaLab

Select the Kinematic group and, inside this, the Particles module. Erase the content of the chalkboard. And add one element Mobile in X and one element Stationary reference system. As show the image below: We know the end time, 7 seconds. Then in the element Stationary reference system write this.

tf

7

To the element Mobile in X, we assume that the car begins its movement from the X coordinate 0 and at the time 0. Also, we assume that its movement is in the direction of the positive X axis. But, as we want the final velocity in km/h, we need write:

vf @ km/h

To the final velocity. As show below:

Name

Car

ax

3

xi

0

vxi

0

ti

0

xf

d

vxf

vf @ km/h

Where d is the final X coordinate, an unknown data. To this example, the name of the mobile Car is irrelevant. Now click in the icon Solve to get the answer.

d = 73.500 m ;  vf = 75.600 km/h ;
Status = success.