An Antarctic rescue system consists of a lead snowmobile and a medical sled connected by a light, rigid coupling rod. The snowmobile has a mass of 50 kg and the medical sled has a mass of 30 kg. A driving force is provided by a winch cable attached to the front of the snowmobile, exerting a tension of 120 N at an angle of 25∘ 25^\circ\,25∘ above the horizontal. The system accelerates forward from rest across a level ice field at a constant rate of 0.6 m s-2.
The snowmobile experiences a constant resistance to motion of 45 N.
Show that the resistance force acting on the medical sled is approximately 15.8 N.
At the instant the system attains a speed of 1.5 m s-1, the winch cable snaps. (i) Assuming the resistance forces on both the snowmobile and the sled remain constant, determine the magnitude of the thrust in the coupling rod while the system is decelerating. (ii) Calculate the distance, ddd, that the system slides from the moment the cable snaps until it comes to a complete halt.
State one modelling assumption you have made about the coupling rod.