A race car is moving with a velocity of 144 kilometers/hour. The driver applies the brakes, and the car comes to a halt in 12.0 seconds. What is the acceleration of the car after 12.0 seconds?. a) - 12.0 meters/second^2. b) - 3.3 meters/second^2. c) 3.3 meters/second^2. d) 10.3 meters/second^2

Velocity of the race car = 144 kilometers/hour

It needs to be converted to meters per second because the answer is in meters per second.

Then

Velocity of the race car = (144 km / hr) x (1000 m / 1 km) x (1 hr / 3600 s) meters/second

= 40 meters/second

Initial velocity of the race car (V1) = 40 m/s

Final velocity of the race car (V2) = 0 m/s

Time taken by the car to come to a halt = 12 seconds

Acceleration of the car = (V2 - V1) / time

= (0 - 40) / 12

= - 3.3 m/s^2

From the above deduction, we can conclude that the correct option among all the options that are given in the question is option "b".

To answer, first, convert the given velocity in km/h to m/s as shown below,

(144 km / hr) x (1000 m / 1 km) x (1 hr / 3600 s) = 40 m/s

The acceleration (a) is solved by through the equation,

a = (Vf - Vi) / Δt

where Vf and Vi are final and initial velocities, respectively and Δt is change in time. Substituting the known values,

a = (0 - 40 m/s) / 12 s = - 3.3 m/s²

Thus, the answer to this item is letter B.