4 A student says that an electromagnet is stronger when it has an iron core because the electric current flows through the iron as well as the wire. Is this correct? What would
you say to the student?

b.a device that inputs heat into a cool object

jupiter is the largest planet in our solar system, having a mass and radius that are respectively, 318 and 11.2 times that of earth. suppose that an object falls from rest near the surface of each planet and that the acceleration due to gravity remains constant during the fall. each object falls the same distance before striking the ground. determine the ratio of the time of fall on jupiter to that on earth.