The current theory of the structure of the Earth, called plate tectonics, tells us that the
continents are in constant motion. Assume that the North American continent can be represented by a slab of rock 5050 km on a side and 35 km deep and that the rock has an average mass density of 2760 kg/m3. The continent is moving at the rate of about
1.4 cm/year. What is the kinetic energy of the continent?