INCLINE PLANE PERFORMANCE ASSESSMENT

Transcription

1 1 INCLINE PLANE PERFORMANCE ASSESSMENT SECTION I Your Name: (Last) (First) Male or Female Date of Birth: (please circle) (month day year) Today's Date: (month day year) INSTRUCTIONS In this activity you will be working by yourself. You can write your answers directly on these pages. Before you look at the equipment in the bag in front of you, we want you to think about the concepts of force and motion.

2 PART I: Planning and Design 2 Suppose you had to push a 1 kg. ball and a 5 kg. ball up a steep hill. 5 kg. 1 kg. Will it be harder to push the 1 kg. ball or the 5 kg. ball up the hill? Why?

3 The amount of force you need (how much you have to push or pull) to move an object up a slope depends on the weight of the object. 3 That means it will take more force to push the 5 kg. ball up the hill than the 1 kg. ball. 1 kg. 5 kg. Another thing to know!!!! The amount of force you need to move an object up a slope also depends on the steepness of the slope. Let's say you now had to push the 5 kg. ball up a smaller, less steep hill. This time you would not have to push as hard!! 5 kg.

4 Now you can take the equipment out of the box in front of you. You should have the following things: 4 EQUIPMENT Incline Plane with Ladder Truck with string and hook Bucket 4 Marbles 1 large blue 1 small blue 1 large green 1 small green Washers Set up the incline plane and ladder so that the incline plane is at level 2. It should look like this: 5 High Slope Low Slope

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6 Put the truck on the incline plane. Run the string over the pulley (spool) and underneath the rung of the ladder so that the hook hangs down over the incline plane. Put the bucket on the hook. It should look like this: 6 5 Truck 4 3 Pulley 2 1 Bucket Practice pulling the truck up the incline plane by placing washers in the bucket. The truck should move to the top of the ramp. Putting washers in the bucket is a measure of the amount of force needed to pull the truck up the incline plane. MORE WASHERS = MORE FORCE

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8 8 Frank and Al are wondering if they will need more force or less force to pull the truck up the incline plane if they change the weight of the truck by adding marbles to it. Suppose you add two large marbles to the truck. Will you have to put more washers or less washers in the bucket to pull the truck up the incline plane? How does the amount of force needed to pull the truck change when the weight of the truck changes?

9 Now let's think about a different problem. 9 Frank and Al have different ideas about how much force they would need to pull the truck up the incline plane when the incline plane is at different levels of the ladder. Frank thinks that it will take more force to pull the truck up the incline plane when the incline plane is at a high slope than when it is at a low slope. BUT Al doesn't think that changing the slope of the incline plane matters. He thinks that it will take the same amount of force to pull the truck up the incline plane at any slope. Can you think of an experiment you could do to test who is right? You can use the equipment in front of you to figure out how you could design an experiment. BELOW, write down the steps you would follow to do your experiment (if you need more space, you can write on the BACK of this page). 1

10 PART II: Performance 10 Now let's see who is right. REMEMBER: Frank thinks that it will take more force to pull a truck up an incline plane when the incline plane is at a high slope than when it is at a low slope. BUT Al doesn't think that changing the slope of the incline plane matters. He thinks that it will take the same amount of force to pull the truck up the incline plane at any slope. Use the equipment in front of you to test if Frank is right or Al is right. Write down your results in the table below. SLOPE (Board) FORCE (Number of Washers) PLEASE RAISE YOUR HAND FOR

11 11 SECTION II OF THE TEST

12 12 INCLINE PLANE PERFORMANCE ASSESSMENT SECTION II Your Name: (Last) (First)

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14 PART III: Analysis and Interpretation 14 Frank and Al conducted an experiment to test out their ideas. They used an incline plane and ladder, a truck with string and a hook, a bucket, and washers as a measure of force. Frank and Al did their experiment to find out who was right. This is what they did: 1. They set up the incline plane so that it was at level 1 of the ladder. They set up the truck on the incline plane. 2. They added washers to the bucket until the bucket fell down to the bottom. Then they wrote down how many washers they used. 3. They did steps 1 and 2 for each level of the ladder. They always returned the bucket to the top before putting the washers in.

15 Frank and Al wrote down their results in the table below. 15 SLOPE FORCE (Level of the Ladder) (Number of Washers) Use the information from the table to graph the findings from Frank's and Al's experiment. FORCE (Number of washers) SLOPE (Level of the Ladder)

16 Look at the results Frank and Al got. How did the amount of force needed to pull the truck change when the slope changed? 16

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18 PART IV: Application 18 The city of Santa Barbara wants to build a new Recycling Plant. The city officials are trying to decide where to build the Recycling Plant. Before they can make their decision they have to think about two things: 1. The city has very little money to spend on gasoline for the recycling trucks. 2. The people of Santa Barbara may not like the noise and pollution from the Recycling Plant. Santa Barbara has the choice of two locations to build the Recycling Plant: 1. They can build the plant on top of a steep hill. Here the noise and smoke from the plant won't bother anyone. OR 2. They can build the plant down low, in a field next to the railroad station. The railroad station is always full of people coming and going to work. The problem is where to build the Santa Barbara Recycling Plant!

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20 Before you think about where you would build the recycling plant, let's review what you learned earlier. 20 In the activity you did earlier, you looked at the relationship between the slope of an incline plane and the amount of force needed to pull a truck up the incline plane. What you should have noticed was that the steeper the slope of the incline plane, the more force it took to pull the truck up the incline plane. In this new problem, the Santa Barbara city officials have to decide whether to build the new Recycling Plant up high on a hill away from the people, OR down low in a field near the train station. However, the city officials must remember that they do not have lots of money to spend on gasoline. Gasoline is important because it provides the trucks with the force to move. The city officials have asked people to send in letters with suggestions where to build the Recycling Plant. Using what you learned in the activity you did earlier, please write a letter to the Santa Barbara city officials with your suggestion for the location of the Recycling Plant. Be sure to carefully explain to the city officials why you chose the location that you did. PLEASE WRITE YOUR ANSWER ON THE NEXT PAGE.

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