simNewton Lab

For this lab you will be accessing some on-line simulations of balls moving in "perfect" conditions. You will be able to see, for instance, how a ball acts if you give it a tap if there were no resistance at all. The URL for this lab is:

http://www.public.iastate.edu/~liuhc/flash/newton/home.html

Activity 1.1

To start this activity, click on the first item in the first column. All of the first column activities involve motion to the left and right in a straight line. If you have trouble and the screen freezes without allowing you to play the game, you probably need to download Flash 5. You can download Flash on the page linked above.

Before you begin any exercise, click on the button to show borders on the path. That will keep the dot in view at all times. Also click on the button to show the trajectory. This allows you to see the dotprints (not footprints, after all) of this dot as it moves. One dotprint represents one second of motion.

In this game, your goal is to make the dot hit the target with as high a velocity as you can. You can apply "impulses" to the dot using the "s" for a left impulse and "a" for a right impulse. (Each impulse gives a quick "kick" to the dot.)

You should play the game several times before you try to answer the following questions. For this and the remaining activities, please answer all of the questions within a separate Word document. At the conclusion of the lab you can e-mail your answers to your instructor.

Questions

1. What was the highest velocity you were able to reach?
2. Describe what you did to reach your highest velocity.
3. What does the "datacross" in the lower part of the window tell you?
4. What happens to the space between dotprints when you apply more impuses to the dot?

Activities 1.2 - 1.4

In this game, choose the "apply border" option near the top of the left window. You will apply impulses to the dot using the "a" and "s" keys for horizontal impulses and "w" and "z" keys for up and down impulses respectively. The goal is to make the dot get to and stop on the target at the correct speed. A timer will show how long it takes you to complete the task. Try to do it in as short a time as possible.
Questions

1. What was your fastest time?
2. Describe what you did to get your fastest time so that someone else could learn how to do it.
3. What does a "negative velocity" mean?
4. Draw a datacross to show a dot that has a velocity of -4 horizontally.
5. What symbols could you imagine (other than the datacross) to depict a dot with a velocity of +3 or -2?
6. If the dot were invisible, you could still tell if it was stopped or not. Explain how.
7. What number would you use to record the velocity of a stopped dot?
8. How can you tell whether a dot is slowing down or speeding up by looking at the dotprints?

Activity 1.2 - 1.4: No End Walls

This time things will get harder/ In the game. deselect the borders option so that you have no end walls. Again use the a/s or w/z keys to apply impuskes to the dot. The target will only catch the dot if it is moving at the specified velocity.

Beware! The dot can go off the screen. But you have the datacross to help you out. A timer will time how long it takes you to complete each game. The first few times you play, take you time and think hard about what you are doing. Then, see how quickly you can complete the game.-

1. If the dot were moving at a velocity of 3 and you wanted it to move at a velocity of 4, what impulses would you give it?
2. If the dot were moving at a velocity of 5 and you wanted it to move at a velocity of 4, what impulses would you give it?
3. If the dot were moving at a velocity of 1 and you wanted it to move at a velocity of -1, what impulses would you give it?
4. For the given cases, create a diagram, picture or some other representation to show exactly what impulses you would give the dot to make it hit the target with the specified velocity: Hit at velocity = 5. Target is to the right of the dot.
a. Hit at a velocity = -3. Target is to the left of the dot.
b. Hit at a velocity of -4. Target is to the right of the dot.

Activity 2.1 - 2.3: Moving in Two Dimensions

Explore these activities until you think that you understand how the impulses are affecting the dot's motion.

Questions

1. For a corner-shaped path as in activity 2.1, what impulses are needed to get the dot from one end to the target at the other end?
2. For the activities that had the dot off-screen, how could you twll where the dot was?
3. In general, how do you make a dot do a right angle turn? Why does this work?
4. For a path that has two 45 degree turns, as in the maze, explain or draw a picture of the sequence of impulses needed to navigate the path.
5. If, at the beginning of the path in number 4 you give the dot one impulse to the right, does the dot continue at the same speed when you make it go diagonally? How do you know?
6. In general, how do you make the dot move diagonally? Why do you think this works?

When you have completed this part of the lab, go on to the remaining examples (2.4 - 2.6 and 3.1 - 3.7). Please be sure to ask questions on the discussion board so you can exchange ideas with your classmates. Turn in this part of the lab as a separateWord document.