Question

The model airplane in Figure 5.6 is flying at a speed of 13.6 m/s on a horizontal circle of radius 19.1 m. The mass of the plane is 1.20 kg. The person holding the guideline pulls it in until the radius of the circle becomes 10.6 m. The plane speeds up, and the tension in the guideline becomes four times greater. What is the net work done on the plane?