What is the concept called when the poles of an electromagnet were to flip?

Mike walks 100 meter north, then walks 30 meters south. after this, he walks another 10 meters north. what is the magnitude of his total displacement during this walk, in meters?

The respiratory system removes oxygen and water from the body. select the best answer from the choices provided t f

Since the energy was not raising the temperature of the water during these segments, what was the energy used to do instead? your answer must include an explanation of what is happening to the molecules.