1. For each of the cases in Figure 21-4, identify whether the magnets will attract or repel one another. S N N a. S S N b. S N N C. S N Figure 21-4 2. When you break a magnet in half, how many poles does each piece have? 3. Which of the compass-needle orientations in Figure 21-5 might correctly describe the magnet's field at that point? (b) (c) (a) (d) S (F) (e) Figure 21-5 4. Physics in Action Satellite ground operators use the feedback from a device called a magnetometer, which senses the direction of Earth's magnetic field, to decide which torque coil to activate. What direction will the magnetometer read for Earth's magnetic field when the satellite passes over Earth's equator? 5. Physics in Action In order to protect other equipment, the body of a satellite must remain unmagnetized, even when the torque coils have been activated. Would hard or soft magnetic materials be best for build- ing the rest of the satellite? Ma