Hi there!
[tex]\large\boxed{-12,600 N}[/tex]
Recall that the equation to calculate force is:
F = m · a where m = mass, a = acceleration, and F = net force.
Since we are given the velocity, and time needed to stop, we can calculate the acceleration using the following kinematic equation:
vf = vi + at
The initial velocity is 36 m/s and the final velocity is 0 m/s, therefore:
0 = 36 + at
Move 36 to the other side and plug in the given time:
-36 = 4a
Divide both sides by -4 to find a:
-36/4 = a
a = -9 m/s².
Since the acceleration is -9 m/s² and the mass is 1400 kg, use the above force equation to solve:
F = -9 × 1400 = -12600 N. (negative refers to the force working in the opposite direction of the car's travel. If simply needing the magnitude of the force, it would be 12600 N)
