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 4200 km on a side and 29 km deep and that the rockhas an average mass density of 2900 kg/m3.The continent is moving at the rate of about4.2 cm/year. A. What is the mass of the continent?B. What is the kinetic energy of the continent? C. A jogger (of mass 70 kg) has the same kinetic energy as that of the continent. What would his speed be?