Final answer:
The questions provided require knowledge of Physics, focused on high school level concepts of forces, motion, and energy. They involve solving problems using kinetic energy calculations and Newton's laws of motion.
Step-by-step explanation:
The subject matter of the questions provided is primarily related to Physics, focusing on the concepts of kinetic energy, forces, acceleration, and the principles of momentum conservation. These questions are typical at the high school level, where students are expected to apply Newton's laws of motion and work-energy theorems to solve problems regarding the motion of various objects, including dogs pulling sleds, children in wagons, and comparing the kinetic energies of moving bodies.
When calculating kinetic energy, the formula ½mv² is used, where 'm' is the mass and 'v' is the velocity of the object. The concept of a net force leading to acceleration can be found using Newton's second law, F = ma, where 'F' is the total force applied, 'm' is the mass of the system, and 'a' is the acceleration produced. The principle of momentum conservation explains the motion of bodies after an interaction, such as two masses moving away from each other, as seen in the example of a child dropping a ball from a wagon.