A car has an initial velocity of 12 m/s and is brought to rest over a distance of 45 m. The acceleration of the car is

Using the kinematic equation v² = u² + 2as, where v = 0 (brought to rest), u = 12 m/s, and s = 45 m. Substituting: 0 = (12)² + 2a(45), giving 0 = 144 + 90a, so a = −144/90 = −1.6 m/s². The negative sign indicates that the acceleration is in the direction opposite to motion, i.e., deceleration, which is consistent with the car being brought to rest.