1. The problem statement, all variables and given/known data An 85 kg tobbogan that was originally accelerating at 3.0 m/s2 on frictionless snow hits a bare patch of concrete that exerts a force of friction on the sled of 180 N, what will the new acceleration be? 2. Relevant equations F=ma 3. The attempt at a solution Ok so this was originally a 2 part question but I merged it into one. I already calculated the applied force of the tobbogan on frictionless snow which is 255 N east. Now I have to find its acceleration when it hits the concrete. So I got the Fnet by subtracting the applied force by the force of friction. 255-180= 75 N east. So now I do a=F/m. So the acceleration by my understanding should be 75/85 which is 0.88 m/s2. But the answer sheet says that it is 0.94 m/s2.