Final answer:
The resistive force exerted by the water on a 456kg ship moving at constant velocity with a 67N forward thrust is 67N. The upward buoyant force is equal to the ship's weight, thus it's 4472.16N.
Step-by-step explanation:
When a ship of mass 456kg is moving at a constant velocity, the net force in the direction of motion is zero, indicating that the forward thrust and the resistive force exerted by water are equal in magnitude. The engine generates a forward thrust of 67N, so the resistive force of water on the ship will also be 67N, opposing the direction of motion.
The buoyant force on the ship is equal to the weight of the water displaced by the ship, due to Archimedes' principle. Since the ship floats without accelerating vertically, the buoyant force must equal the gravitational force on the ship, which is the product of its mass (456kg) and the acceleration due to gravity (9.81m/s2). Therefore, the upward buoyant force equals 456kg × 9.81m/s2 = 4472.16N.