Inertia Lab Inertia Lab Group Problems You must read, consider, and attempt each problem, as you do not know which problem your group will present. 1. You have probably already seen a "magician" yank a tablecloth from underneath a fully set table, and perhaps even tried it yourself. The first thing you need to do it either reflect on your past experience, or try it yourself. 2. Over on the lab table grab three water bottles 3. Leave one empty, fill one half ways, and fill the last one all the way 4. Put a paper towel underneath the bottles 5. Predict what will happen if you pull the paper towel parallel to the tabletop surface slowly, and also what a quick yank will do. Explain the difference (and why there is one) in both situations. (make sure your paper towel does not get wet) 6. Answer if your predictions were correct. (Not everyone gets it the first time.) 7. Explain, using Newton’s 1st Law, the difference between the water bottles. Why did differing mass have an effect on the situation? Using Your Head 1. While repairing your boat dock, you find that your hammer’s head (the metal part) is getting loose. What are two different ways that you could fix your hammer by getting the metal to fit snugly on the wooden hammer handle? One way relies on Newton’s 1st Law and the inertia of the hammer’s head. Describe how this works. 2. Once you use this great idea, you decide to have a nice, long nap in your boat. After a few minutes, you wake up to find that your boat has drifted about a meter from the dock (you forgot to tie it down). You don’t have anything long enough to pull yourself to the dock, and you are terribly allergic to water (rough allergy, huh?). You figure that one meter is no trouble for you to jump, but, using your head and Newton’s 1st Law, you decide to call for help instead. Explain why. Pennies From Heaven 1. You will be practicing your skills with an old parlor trick: the penny catch. First, bend your elbow completely, so your wrist is as close to your shoulder as possible. 2. Now, raise your elbow directly out from your body so that your forearm is completely horizontal (parallel with the ground). By balancing a stack of pennies right on your elbow (or as close to it as possible) and then quickly swinging your elbow down, you can amaze your friends and demonstrate Newton’s 1st Law (with some practice). Explain how this is an example of inertia. 3. Now comes the fun part. See who in your group can snatch the largest stack of pennies. Start with 5 (once you know how), and work your way up. What is the record for your group? NOTE: Be sure not to hit others with the pennies, as you can knock them quite fast. Just a Quick Flick 1. To start this problem, you will need the following objects: an index card, a penny, a large glass of water, and a ruler (or other short stick). 2. Place the index card on top of the glass of water, and the penny in the middle of the index card. With the ruler, you have all the equipment you need. 3. The goal: Try to make the penny end up in the glass of water without (a) moving the glass, (b) breaking or bending anything, (c) having the card stay on the cup, and (d) using anything except the ruler to do so. 4. How do you think you can accomplish this? How does Newton’s 1st Law play a role here? This is a workout? 1. Try to drop a tennis ball on a target as you run past the target. Mark a piece of paper with an X. Stand about 5 meters away from the target. Run about 5 meters toward the paper as fast as you can and drop the tennis ball on the target. Write observations about where the ball landed when you dropped it. 2. Why did the tennis ball land where it did? 3. Draw a diagram of the path of the tennis ball as you dropped it while running by the target. Draw a diagram of how you would have to throw the tennis ball to hit the target if you were standing 10 meters away from the target. The Gambler Kenny Rogers 1. Stack five poker chips in a pile on top of each other. Knock the bottom chip out from underneath the other chips by hitting it with the thin edge of a plastic knife. You will need to do this quickly. You may not be successful in knocking just the bottom chip out on the first try. You may need to practice several times before you get it. 2. Explain why only the bottom chip moved in terms of inertia.
