We need to find the net force. We are given a starting and final velocity, the length of time the acceleration took place and the total weight of the car. We can use F=ma to calculate the net force. Since mass is given only the acceleration has to be calculated. We can use the suvat equation v=u+at. Rearrange to a= (v-u)/t. Plug in the correct numbers a = (20-10)/10. Acceleration = 1ms-2. Now plug that into F=ma. F=2000x1=2000N.