Inertia Smorgasbord

Name:______Block:______Date:_____/_____/_____ IP 614 Inertia Smorgasbord

The tendency for things to resist changes in motion was what Galileo called inertia. Isaac Newton later refined this idea and made it his first law, appropriately called the law of inertia. Here’s an excerpt from Newton’s book Principia: law 1: Every material object continues in its state of rest, or uniform motion in a straight line, unless it is compelled to change by forces impressed upon it. Essentially this means that things keep doing what they are doing, unless something happens to change that. In the following lab, first predict what will happen in the following examples of inertia. Next carry out each activity and record each outcome in the spaces provided. This is a station lab. You do not have to do these in order. Go around to each of the 5 stations and try each thing.

1. Pennies over cups Predict the motion of the penny: Describe the motion of the penny. Be sure to talk about its velocity, speed, & acceleration. 1a. Watch the penny for a while...

1b. Now quickly flick the index card away. Watch the penny.

2. Chalk on hoop on bottle. Predict the motion of the chalk: Describe the motion of the chalk. Be sure to talk about its velocity, speed, & acceleration. 2a. Watch the chalk for a while...

2b. Now quickly flick the hoop away. Watch the chalk.

3. Silly hangar hat. Predict motion of the blobs: Describe the motion of a blob. Be sure to talk about its velocity, speed, & acceleration. 3a. Balance hat on your head and turn VERY SLOWLY around.

3b. Balance hat on your head and turn your head QUICKLY to the side.

4. Plate, Strange Plate and Predict the motion of the marble: Describe the motion of the marble. Be sure to marble. talk about its velocity, speed, & acceleration. 4a. Put the uncut plate on the table and give the marble a push so that it rolls around the inside of the rim.

4b. Put the plate with the cutout on the table and give the marble a push so that it rolls around the inside of the rim. Carefully watch what happens after the marble leaves the plate!

5. Table Cloth with Dish and Predict the motions of the dish and the napkin: Describe the motion of the dish and describe the napkin motion of the napkin. Be sure to talk about velocity, speed, & acceleration. 5a. Put the dish and the napkin on the cloth and pull the cloth very slowly. (Don’t break my dish.) 5b. Now pull the cloth very quickly, and sort of downward. If you can’t do it, get your teacher to help you. Name: ______Block:_____ Date: _____/_____/_____ IP 614 Inertia Smorgasbord Questions The following questions ask about the inertia smorgasbord lab. Answer all questions in complete sentences.

1. Pennies over cups: a. In the first part of this experiment, you watched the penny for a while. The penny should have stayed at rest (its velocity should have been zero). Did you see the penny stay at rest? ______Why did the penny stay at rest? Use inertia to explain why the penny stayed at rest.

b. In the second part of this experiment, you flicked the index card away from under the penny. The penny should have fallen into the cup. Did you see the penny fall into the cup? ______Why didn’t the penny move to the side with the card?

Why did the penny fall into the cup?

2. Chalk on hoop on bottle: a. In the first part of this experiment, you watched the chalk for a while. The chalk should have stayed at rest (its velocity should have been zero). Did you see the chalk stay at rest? ______Why did the chalk stay at rest? Use inertia to explain why the chalk stayed at rest.

b. In the second part of this experiment, you pulled the hoop away. The chalk should have fallen into the bottle. Did you see the chalk fall into the bottle? ______Why didn’t the chalk move to the side with the hoop?

Why did the chalk fall into the bottle? 3. Silly hanger hat: a. In the first part of this experiment, you balanced the hat on your head and turned very slowly around. The hanger hat should have spun with you. Did you see hanger hat move with you? ______Why was the hanger hat able to move with you?

b. In the second part of this experiment, you balanced the hat on your head and turned very quickly. The hanger should have stayed at rest relative to the ground. Did you see the hanger hat stay at rest? ______Why didn’t the hanger hat move with you as it did when you moved slowly? Use inertia in your explanation.

Why were the blobs so massive? Would the experiment have worked as well if the blobs were much smaller?

4. Plate, Strange Plate, and Marble: a. In the first part of this experiment, you rolled the marble around the inside rim of the uncut plate. The marble should have traveled in a circle. Did you see the marble travel in a circle? ______Since the marble was moving in a circle, it was accelerating, and needed something to push it in a circle. What was pushing the marble in a circle?

b. In the second part of this experiment, you rolled the marble around the inside rim of the cutout plate and watched what happened when the marble left the plate. The marble should have traveled in a straight line when it left the plate. Did you see the marble move in a straight line? ______Why didn’t the marble continue to move in a circle when it left the plate? Use inertia in your explanations. 5. Table Cloth with Dish and Napkin: a. In the first part of this experiment, you put the dish and the napkin on the cloth and pulled the cloth very slowly. The plate and the napkin should have moved with the cloth. Did you see the plate and napkin travel with the cloth? ______What caused the plate and napkin to get pulled to the side with the cloth?

b. In the second part of this experiment, you put the dish and the napkin on the cloth and pulled the cloth very quickly. The plate should have been left behind on the table and the napkin should have moved with the cloth. Did you see the plate get left behind so it landed on the table? ______Did you see the napkin move with the cloth? ______Why didn’t the plate get pulled to the side with the cloth? Use inertia in your explanation.

Why did the napkin get pulled to the side with the cloth? Use inertia in your explanation.