Unit 4 Contents

1. Some satellites circle the Earth at the same speed all the time. Others speed up and slow down as they orbit the Earth. A scientist watched a satellite through a telescope for three minutes. She saw that it traveled 232 kilometers in the first minute, 246 kilometers in the second minute, and 259 kilometers in the third minute.
1. What is the total distance traveled by the satellite over the three minutes?
2. Now estimate the distance. Was your answer for Question 1A reasonable?
1. Out of the 4284 orbiting satellites launched by the United States, 3231 are no longer being used. About how many satellites does the United States have in orbit that are still in use?
2. Did you estimate your answer for Question 2A or find an exact answer? Explain why.

Meteors, or “shooting stars,” are objects (usually very small ones) that burn up brightly as they fall to the Earth from outer space. During meteor showers, many of these can be seen streaking across the sky on a clear night. On a camping trip over the summer, Jacob counted the number of meteors he could spot crossing the night sky during a meteor shower.

3. On Monday, Jacob spotted 9 meteors. On Tuesday, he spotted 13. He counted 21 on Wednesday, 12 on Thursday, 17 on Friday, and 54 over the weekend.
1. How many meteors did Jacob see from Monday to Friday?
2. How many did he see all week?
3. Did Jacob see more meteors from Monday to Friday or over the weekend?
4. How many more meteors did he see during the week than over the weekend?