An SUV is traveling at a speed of 18 m/s. If the SUV has a mass of 1,550 kg, what force must be applied to stop it in 8 seconds?

This is a standard dynamics problem that can be solved using equations of motion. You may recall the three equations of motion:

1.) v = u + a*t

2.)(v^2) = (u^2) + 2*a*t

3.)s = u*t + 0.5*a*(t^2)

Here, v = final velocity; u = initial velocity; t = sec; a = acceleration.