Question

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 5900 km on a side and 26 km deep and that the rock has an average mass density of 2800 kg/m³. The continent is moving at the rate of about 4 cm/year. What is the mass of the continent.

Answer 1

To find the mass of the North American continent, you multiply the volume (length, width, depth) by the density. After converting all measurements to meters, the mass is found to be approximately 2.51 x 10^21 kilograms.

Step-by-step explanation:

To calculate the mass of the North American continent based on the provided dimensions and the average mass density, you use the formula for mass which is mass = volume × density. The volume of the slab representing the continent is found by multiplying its length, width, and depth. In this case, the slab is 5900 km on a side and 26 km deep, which must be converted into meters to match the density units (kilograms per cubic meter).

The volume in cubic meters is: (5900 × 103 m) × (5900 × 103 m) × (26 × 103 m) = 8.98 × 1017 m3. The mass density is given as 2800 kg/m3, so the mass of the slab is:

Mass = volume × density = 8.98 × 1017 m3 × 2800 kg/m3 = 2.51 × 1021 kg.

Therefore, the mass of the North American continent, as represented by this model, is approximately 2.51 × 1021 kilograms. It's important to note that the actual mass of the continent would be affected by a variety of factors, including varying densities of different types of rocks and the depth of the continental crust, which varies in different locations.