A child applies a force F? parallel to the x-axis to a 10.0-kg sled moving on the frozen surface of a small pond. As the child controls the speed of the sled, the x-component of the force she applies varies with the x-coordinate of the sled as shown in figure (Figure 1) . Suppose the sled is initially at rest at x=0. You can ignore friction between the sled and the surface of the pond.

Part A
Use the work-energy theorem to find the speed of the sled at 5.0m .
Part B
Use the work-energy theorem to find the speed of the sled at 12.0m .
Please show me how to find part A and B