How roofs are lifted off building in tornado?

Disney, viacom and aol time warner are examples of

As a pendulum bob swings back and forth several times, the maximum height it reaches becomes less and less. this is because more and more of the pendulum bob's energy is being transformed into a. heat energy b. kinetic energy c. potential energy d. kinetic energy and potential energy

What’s #16 asking and how do i solve it?