1. The problem statement, all variables and given/known data A train that runs 140 km / h requires about 700m to stop. Calculate the average acceleration of the train while braking. 2. Relevant equations v: x/t 3. The attempt at a solution v= x/t so t= x/v= 700m/ (38.89m/s)=18 s Now to find acceleration a= v/t a= 38,89m/s / 18s =2,160 m/s^2 They're asking the average so 2,160 m/s2 is our initial acceleration therefore 0-2,160 m/s^2 / (2) = -1,08024 Is it the correct formula to use ? or is it wrong ???