All of the following problems deal with Jimmy and his friend. Draw a FBD for each. Assume the total mass of Jimmy and his sled is 50kg. Disregard air resistance.

1. Jimmy is sledding down the side of a hill, using his iPhone as an accelerometer. The phone measures his acceleration to be 2.5 m/s^2. What is the net force he is experiencing? (125 N)
2. Jimmy is being pulled back up the hill by a "friend" who owes him $5. Assuming his friend applies 18N of force up the hill and gravity and friction each apply 8N of force down the hill, what is Jimmy's acceleration? (0.04 m/s^2)
3. At the top of the hill, the snow is level and flat. Jimmy runs with his sled up to a speed of 3 m/s before diving onto it and sliding to a stop (still on the level part of the snow). Assuming it takes Jimmy 2 s to slide to a stop, what is his acceleration? What is the net force during these two seconds? What is applying the force? (-1.5 m/s^2, -75N, friction)
4. Jimmy is being pushed horizontally across the level part of the snow at a constant velocity. If his "friend" applies 15N of force in order to maintain Jimmy's velocity, what is the coefficient of friction between Jimmy's sled and the snow? (0.03)
5. Jimmy's "friend" finally gets tired of having to pull Jimmy around. Using the heel of his boot, he expeditiously pushes Jimmy down a 45 degree incline and into a grove of trees. Using the coefficient from #4, what will Jimmy's acceleration down the incline be? (-6.7 m/s^2)