الفيزياء الصف الاول الثانوى الترم الثانى

Choose the correct answer :
12-A car of mass 1200 kg is moving with a velocity 20 m/s .If the driver used the brakes and the speed of the car decreased to 8 m/s within 6 sec , then the average force acting on the car during this period and its direction is ……………..