Unit 5 : Activity 5 : Basics of Moving Around in Space : Changing Orbits : Unit Exam

Unit 5: End of Unit Exam

This assignment consists of four parts. The first is a review with a couple of practice questions linked directly to their answers. The second is a short quiz that you take using Blackboard. It will be instantly scored for you by Blackboard; you only get one chance to take it, however, so be sure you are ready! The third part is an essay question. The question appears below; when you are ready to answer it, log on to Blackboard and submit your essay. Finally, for each unit, you should log on to Blackboard and contribute a question, an answer, or a comment to one of the posted topics. If you would like to introduce a new topic instead of contributing to an existing thread, please send your topic idea to your instructor. If you find the material in this unit challenging, you might want to start with the "discussion" part of the assignment in order to get some help with some of the ideas.

To use Blackboard you will need to be signed up as a student in the course. That means that first you must enroll for credit and then you can login to Blackboard. The instructor will verify that you are enrolled in the course and verify your enrollment in EveningStar.

Brief summary of Unit Five:

In this unit we learned how to apply Newton's laws of motion to rockets in orbit around a planet and far away from a planet. We ended with a discussion of how a rocket can change orbits.

Before you go to the quiz, see how you do on these two questions. If you have trouble, you might want to review the unit, send a question to the discussion group, or seek help from the instructor.

Practice Question One

Name two factors that you need to consider for motion near the Earth's surface but that you can ignore in an orbit around the Earth.

Practice Question Two

Suppose you are in a circular orbit around the Earth in the Space Shuttle. The nose of the craft is aimed in the direction of motion. You briefly turn on your thrusters. What happens to your orbit?

a. nothing
b. it gets smaller and remains circular
c. it gets larger and remains circular
d. it gets smaller and more elliptical
e. it gets larger and more elliptical

When you are ready, login to Blackboard and take Quiz Five.

You will get instant feedback on your score on Quiz Five (and your instructor will also be informed of your score). If your score is OK, you may proceed directly to the Essay Question Four on Blackboard. Otherwise, you might want to look at what you missed, ask your instructor about questions you missed, or review relevant parts of the unit.

Essay Question

A baseball game in space. Taking a break from assembling the space station, a bunch of astronauts decide to try playing baseball. They put on their spacesuits and jetpacks and go "outside" to play. In each part, when I say "what happens to ..." I mean does he or it start or stop moving? How fast and in what direction? In each case explain how you know the answer to the question.
A. After each of the players has found a good spot and used his jetpack to stop moving relative to the space station, the pitcher revs up and throws what on Earth would be a good curve ball. What happens to the ball in space? What happens to the pitcher? Assume the ball has a mass of 0.1 kg, the pitcher has a mass (in his suit) of about 100 kg, and he pitches with a speed of 10m/s.
B. The batter takes a crack at the ball and connects; the ball heads back the way it came at about twice the speed it had when it arrived. What happens to the batter?
C. The ball heads straight out into left field, where another astronaut catches it. What happens to him?
D. Would any of these answers be different if they were playing inside the space ship and without their space suits? Explain.


Don't forget to contribute to the discussion on Blackboard on one of the topics in this unit!