To give a 19-kg child a ride, two teenagers pull on a 3.6 kg- sled with ropes. Both teenagers pull with a force of 55 N at an angle of 35 degrees relative to the forward direction, which is the direction of motion. In addition, the snow exerts a retarding force on the sled that points opposite to the direction of motion, and has a magnitude of 57 N . Find the acceleration of the sled and child. What I am doing is adding the weight of the child and the sled and using that as my mass and then finding the acceleration of the two kids pulling the kid by using a=f/m and then I did that same thing for the kid..... I don't know what to do from there....any suggestions? What am I forgetting?