You drive a dog sled of mass 11 Ibm carries a load of 219 Ibm, including the driver (you). It is pulled by a team of 12 dogs, weighing an average of 21 Ibm each. Assume that the runners on your sled have a coefficient of static friction of 0.34 and a coefficient of kinetic friction of 0.14 when on packed snow and your dogs have a coefficient of static friction of 0.65 and a coefficient of kinetic friction of 0.39. Note on units: The ratio between the pounds of force (Ibf) and pounds of mass (Ibm) is the gravitational acceleration at the surface of the Earth (g = 32.2 ft/=2), so that g = _1 1bf = 32.2 ft/s 1 Ibm W = Mg = 1 Ibm x g = 1 lbf Use lbf and ft/s in the answers to these questions. To express a percentage in WebAssign, leave a space after the number, e.g., 30 %. I. Sled at Constant Speed (a) What is the maximum force (magnitude, in lbf) that a single dog can produce? F 1 = (b) What is the force your dogs would have to apply to the sled in order to keep the sled moving at a constant speed? Pmin = (c) Describe how hard each dog must work to keep the sled moving at a constant speed as the percentage of its maximum effort it needs to expend to keep the sled from slowing down. P = II. Sled Starting at Minimum Force (d) What force would your dogs have to apply to the sled in order to get it to start moving? Fi = (e) If the dogs were to provide just enough force to begin moving the sled, what would the acceleration of the dog sled be? (f) What would the pulling force on the dog sled from the dogs be after the sled started to accelerate? Pf = (g) What is the efficiency of the dog sled as defined by the ratio of the force applied to the sled against the force provided by the dogs at the minimum force required to start the motion? (express as a percentage) E = III. Maximum Acceleration of the Sled (h) The dogs were to pull the sled as hard as they could, what would the acceleration of the sled be? amax = (1) What is the force on the sled from the dogs when its acceleration is maximal? Pmax = (j) What is the efficiency of the dog sled as defined by the ratio of the force applied to the sled against the force provided by the dogs at the maximum acceleration? (express as a percentage)