A) 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/m^3. the continent is moving at the rate of about 4 cm/year. what is the mass of the continent. answer in units of kg.
b) what is the kinetic energy of the continent? answer in units of kg.
c) a jogger (of mass 80 kg) has the same kinetic energy as that of the continent. what would his speed be? answer in units of m/s.

Domain eukarya; kingdom plantae should be the answer.

    m₁v₁ + m₂v₂ = (m₁ + m₂)vmomentum is conserved.the left-hand side of the equation represents the momentum in the system before the collision.the right-hand side represents the momentum in the system after the collisionm₁ and v₁ represents the mass and the velocity of the physics blockm₂ and v₂ represents the mass and velocity of the ball of puttyv represents the final velocity of the combined mass.the question states the two masses stick together. they combined mass has its own velocity with the body mass the sum of the two objects' massestheir combined momentum is (m₁ + m₂)vto find the magitude of (m₁ + m₂)v, we need to add the vectors on the left-hand side of the equation: m₁v₁ + m₂v₂.note the diagram. i have positioned the vectors in accordance with their directions.the magnitude of the resultant can be calculated using the pythagorean theorem since this is a right triangle situation (north and west are perpendicular)|(m₁ + m₂)v| =  √[ (m₁v₁)² + (m₂v₂)² ]|(m₁ + m₂)v| =  √[ (1.5kg·8.0m/s)² + (0.40kg·20m/s)² ]|(m₁ + m₂)v| =  14.4 kg m/sfor two significant figures (assuming that 20m/s is two), this rounds to 14 kg m/s