Braking distance. The data in the table shows the braking distance of Cheryl's car travelling at different speeds just before the brakes are applied. Speed 12.5 15 16.7 20 26.7 29.2 33.3 (m/s) Braking distance 7.80 11.3 13.9 20.0 35.6 42.5 55.6 (m) 12 (i) The data can be modelled by d = v²/k +c , where d represents the braking distance in metres, v represents the speed in m/s and k is a non-zero constant. State the value of c and give a reason for your answer.