A tram moves along a straight track towards a stop. Over a period of 6.0 s its velocity falls steadily from 12 m/s to 3.0 m/s.
The direction in which the tram is moving is taken as positive.
What is the acceleration of the tram during this period?
+1.5 m/s2+1.5\ \mathrm{m/s^2}+1.5 m/s2
−2.0 m/s2-2.0\ \mathrm{m/s^2}−2.0 m/s2
−2.5 m/s2-2.5\ \mathrm{m/s^2}−2.5 m/s2
−1.5 m/s2-1.5\ \mathrm{m/s^2}−1.5 m/s2