A car travelling at 14 m/s has to make an emergency stop so applies the brakes and it takes 1.5s to become stationary. What distance has the van travelled in that time?

Assuming constant deceleration we can use the equation s = t(u+v)/2, where u=14m/s, v=0m/s and t=4s. Inputting these values we have that the distance travelled s = 1.5(14)/2 = 21/2 = 10.5m
u = the starting velocityv = the final velocityt = times = the distance travelled