I don't know how to solve these questions and I was wondering if anyone here could help me First question The coefficient of static friction between hard rubber and normal street pavement is about .8. On how steep a hill (maximum angle) can you leave a car parked? Last one A motorcyclist is coasting with the engine off at a steady speed of 20m/s but enters a sandy stretch where the coefficient of friction is .80. Will the cyclist emerge from the sandy stretch without having to start the engine if the sand lasts for 15m? If so, what will be the speed upon emerging? Could the person not give me the answer, but show me how it's done? I would be VERY greatful (preferably with a sum of forces in X and Y directions as I find that easier to understand, but I feel inconsiderate at this point so it's not necessary). Thank you.