The current theory of the srtucture of the Earth, called pate tectonics , tells us that the continents are in constant motion. Assume that the North American continent can be reoresented by a slab of rock 5450 km on a side and 36 km deep and that the rock has an average mass density of 2790 kg/m^3. The continent in moving at the rate of about 3.2 cm/year. Part 1) What is the mass of the continent? Answer in untis of kg. Part 2) What is the kenetic energy of the continent? Answer in units of J. Part 3) A jogger (of a mass 79 kg) has the same kenetic energy as that of the continent. What would hos speed be? Answer in units of m/s.

Pe = 1/2k(x)^2  and .05n/m = .05x10^-9m = x 

Answertraveling around a circular trackexplanation"traveling around a circular track" is the best answer as you could be traveling around a circular track at a constant speed. your velocity would therefore have the same magnitude but will always be constantly direction. since acceleration is the rate of change of velocity, the rate of change will only involve the direction of velocity and not the magnitude.wrong choices: "an object at rest" does not accelerate at all"increasing speed while traveling around a curve" means that the acceleration will not be constant due to only change in direction; it will be constant due to both magnitude and direction"an object in free fall" does not necessarily change direction 

Answer59.2kg; /

Dshould be the right answer i think