A car travels along a straight road with forward direction taken as positive. It passes the origin at t=0 with a speed of 20m/s. The car then slows down uniformly to rest in 4s and immediately accelerates backward (negative direction) at a constant 3m/s2 for the next 2s. What is the car’s displacement relative to the origin at t=6s?
a) 40m
b) 34m
c) 28m
d) 46m