The model airplane in Figure 5.6 is flying at a speed of 23.3
m/s on a horizontal circle of radius 17.3 m. The mass of the plane
is 0.724 kg. The person holding the guideline pulls it in until the
radius of the circle becomes 14.9 m. The plane speeds up, and the
tension in the guideline becomes four times greater. What is the
net work done on the plane?