A car goes from 80 kn/h to 20 km/h in 0.5 h. What is the acceleration in km/h^2? *

In physics, acceleration is defined as the rate of change of the velocity of an object with respect to time. That is A = VF - VI /T; Where A =  Acceleration VF = Final velocity = 20 km VI = Initial velocity = 80 km T= Time = 0.5 hr A = (20 - 80)/ 0.5 = - 60/.5  A = - 120 Km/ hr^2 Therefore, the acceleration of the car is -120 km/hr^2. Because the value is negative, the appropriate name that describe it is deceleration.I Hope this helps