4. Occasionally an asteroid will break into fragments due to a collision. These fragments, which often contain ice, can leave the asteroid belt and make their way to Earth. Upon entering Earth's atmosphere, the fragment would be heated to a high temperature by frictional forces.

a. What would happen to any ice contained within the fragment?

b. What type of phase change would this be?

c. Is this type of change considered a chemical change or a physical change? Explain.

5. Due to frictional interactions with Earth's atmosphere, a large static electric charge could build up on an asteroid fragment as it falls through the atmosphere.

a. Explain how an electric field is generated.

b. Would you expect the fragment to generate an electric field in this situation? Explain why or why not.

c. Describe the different ways a magnetic field can be generated.

d. Would you expect the fragment to generate a magnetic field in this situation? Explain why or why not.

6. A large in-falling fragment could be tracked using radar.

a. What region of the electromagnetic spectrum is typically used for radar? How does the wavelength of radar waves compare to those of visible light (larger, smaller, or about the same)?

b. How can radar be used to determine the distance between the radar station and the asteroid fragment?

c.Explain how radar can be used to determine the speed, and the direction of motion, of the asteroid fragment. Include two examples in your explanation: (1) the fragment is moving towards the radar station, and (2) the fragment is moving away the radar station.