The magnitude of the friction on the cart is 28,56 N
To measure the deceleration of a car, without the value of the time of the movement, the Torricelli equation is used, which consists of:
[tex]{\displaystyle {v_{f}}^{2}={v_{o}}^{2}+2a\Delta s}[/tex]
Where is final velocity, is initial velocity, is acceleration, and is displacement.
Now, substitute the values in the formula:
[tex]0^{2} = (3.5)^{2} + 2a6[/tex]
[tex]0 = 12.25 + 12a[/tex]
[tex]a = -\frac{12.25}{12}[/tex]
[tex]a = -1.02[/tex]
Finally, the value of the acceleration found is multiplied by the mass of the object, thus measuring the friction force:
[tex]F = 28\times-1.02[/tex]
[tex]F = -28.56 N[/tex]
Learn more about friction force at: brainly.com/question/13707283