7.
A car having an initial velocity of 12 meters per second
west slows uniformly to 2.0 meters per second west in
4.0 seconds. The acceleration of the car during this 4.0
second time interval is
(1) 2.5 m/s west
(2) 6.0 m/s west
(3) 2.5 m/s² east
(4) 6.0 m/s east
Proof. Show calculation.