The magnitude of the braking force is given by:
[tex]f=ma=m\frac{{v_f}^2-v_0^2}{2d}[/tex]Replace the values of m=339kg, v_f=3.25m/s, v_0=27.9m/s and d=5.19m to find the magnitude of the braking force:
[tex]f=(339kg)\times\frac{(3.25\frac{m}{s})^2-(27.9\frac{m}{s})^2}{2(5.19m)}=-25,077.1...N[/tex]The minus sign accounts for the fact that the car is decelerating.
Therefore, the magnitude of the braking force is approximately 25,077N.
