Levers Gizmo Answer Key

Name: Ian Bonilla Date: 11-26-2022 Student Exploration: Levers Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes. Vocabulary: effort, first-class lever, fulcrum, lever, load, mechanical advantage, second-class lever, third-class lever Prior Knowledge Questions (Do these BEFORE using the Gizmo.) 1. A lever is a rigid plank or bar that pivots on a fulcrum. Look at the lever in the picture. Where would you push on the lever to lift the rock? With the force the rock provides, I would push the empty plank in order to lift it. 2. Where are some places that you see levers in everyday life? The lever is sometimes referred to as a seesaw in the park. Gizmo Warm-up In the Levers Gizmo, the strongman tries to lift animals by pushing down or pulling up on the lever. The force of his push or pull is the effort The weight of the animal is the load. Both forces are measured in newtons. ● ● ● ● You can move the fulcrum to the left or right by dragging it. You can drag animals to any spot on the lever. You can move the strongman by dragging him. You can change the strongman’s Effort with the slider. 1. Drag the pig to the lever. Try to arrange the lever so that the strongman can lift the pig. What did you do so that he could lift it? I require the men to exert all their strength in raising the pig, which weighs roughly 1000N. Since the pig weighs 2400N, however, that is still insufficient to lift it; thus, in order for the man to lift the pig, I moved it to position 1.5. 2. Did the strongman pull up or push down to lift the pig? The strong man lifted the pig by pulling up. 3. How much effort was needed to lift the pig? 1000N Activity A: First-class levers Get the Gizmo ready: ● ● Remove the pig from the lever. Drag the turkey onto the lever. Question: In a first-class lever, the fulcrum is between the effort (strongman) and the load (turkey). How are first-class levers helpful? 1. Observe: Place the turkey, strongman, and fulcrum at a variety of positions. Each time, pay attention to the smallest amount of Effort needed to lift the turkey. (Note: In this simulation, the lever itself has no mass.) 2. Form hypothesis: When does a lever make it easiest to lift the turkey? The lever makes it simple to raise the turkey because it multiplies the force you apply and transfers that force to the poultry. 3. Experiment: Place the fulcrum at position 3, the turkey at position 4, and the strongman at position 2. Slowly increase the Effort until the turkey is lifted. A. What is the smallest force that can lift the turkey? About 90N of force is required to hoist the turkey. B. How does this effort compare to the turkey’s weight? The turkey weights 100N, which makes it far heavier than the effort in comparison. 4. Revise and repeat: Move the strongman further away from the fulcrum and lift the turkey. A. What is the smallest force that can lift the turkey now? The turkey can now be lifted with 40N of power. B. Which moves more, the turkey or the strongman’s hands? Each moves with the same force. 5. Draw conclusions: A. How does a first-class lever help you lift a turkey? The fulcrum of superior levers is situated between the force and the load. In a first-class lever, the fulcrum is located between the effort and the load, and the effort travels over a significant distance to shift the load over a smaller distance. B. What is the “price” that you pay for using less force? If you wish to raise the turkey with less force, you must stand farther away. 6. Predict: What will happen if the turkey is farther from the fulcrum than the strongman? I believe it will be more difficult for the strong man to lift him. 7. Test: Check your prediction using the Gizmo. Were you correct? Yes, because he needs to exert more force, the strongman finds it more difficult to raise the turkey. Activity B: Get the Gizmo ready: Mechanical advantage ● ● ● Turn on Show grid. Place the fulcrum at position 5. Drag the sheep to position 6. Question: How are forces and distances related? 1. Observe: Move the strongman to a few places on the lever and find the smallest effort needed to lift the sheep at each place. What do you notice? The amount of force required to hoist the sheep increases as you move the guy closer to the fulcrum. 2. Form hypothesis: As the strongman gets further from the fulcrum, what happens to the effort needed to lift the sheep? He can lift the sheep with minimal effort. 3. Experiment: Place the strongman at position 3. He is now 2 meters from the fulcrum. Find the smallest effort needed to lift the sheep. Record it in the table below. Repeat with the strongman at a distance of 3 meters and 4 meters from the fulcrum. (Positions 2 and 1.) Distance from fulcrum to sheep 1 meter 1 meter 1 meter Distance from Fulcrum to strongman 2 meters 3 meters 4 meters Smallest effort needed to lift a 1200 N sheep 310N 250N 140N 4. Analyze: When the strongman’s distance from the fulcrum is doubled (like from 2 m to 4 m), what happens to his effort needed to lift the sheep? If the strong man wants to lift the sheep, he must use twice as much effort. 5. Calculate: The mechanical advantage of a lever is how much it multiplies your effort. If you can lift a 1200-N sheep with only 600 N of effort, the lever doubled your effort, so its mechanical advantage is 2. (Notice you can just divide load by effort: 1200 ÷ 600 = 2.) Calculate the mechanical advantage of the lever with the strongman at each distance: 2 meters: 3.87096774194 3 meters: 4.8 4 meters: 6. Predict: What force will the strongman need when he’s 5 m from the fulcrum? Test your prediction using the Gizmo. Were you correct? Activity C: Second- and third-class levers 8.57142857143 130N Yes Get the Gizmo ready: ● Place the fulcrum at position 6. Question: So far, you have studied first-class levers. How do other kinds of levers work? 1. Set up Gizmo: In a second-class lever, the load is between the fulcrum and the effort. Set up a second-class lever with the turkey between the fulcrum and the strongman. 2. Run Gizmo: Find the smallest effort to lift the turkey using a second-class lever. How does this effort compare to the load? The turkey requires only 60N of effort to hoist, whereas the weight requires roughly 90N. 3. Observe: Does the strongman push this lever up or down to lift the turkey? The strong man pushed the lever up to lift the turkey. 4. Experiment: With the fulcrum still at position 6, put the turkey at position 3 and the strongman at position 0. Find the smallest force needed to lift the turkey. A. What was the force needed to lift the 100-N turkey? 60N B. What is the mechanical advantage of this lever? With second-class levers, a heavy load can be moved with only a modest amount of physical effort. 5. Set up Gizmo: In a third-class lever, the effort is between the fulcrum and the load. Set up a third-class lever with the strongman between the turkey and the fulcrum. When using a third-class lever, the least amount of force required to raise the turkey is 180N. 6. Run Gizmo: Find the smallest effort to lift the turkey using a third-class lever. A. Is the effort larger or smaller than the load? The effort is larger than the load. B. How far was the turkey lifted relative to the strongman’s hands? The turkey was lifted more than the strongman's hands. 7. Predict: Do you think you can lift the pig with a second-class lever? How about a third-class lever? No No 8. Challenge: Try to lift the pig using second-class and third-class levers. Describe your results. Even though the guy uses his entire 1000N of force to push the pig up with the second-class lever, it is not enough to lift the pig, which has 2400N. The third-class lever, meanwhile, produced the same outcome for us. Even though the guy exerts all of his 1000N of force to hoist the pig, which has 2400N of force, it cannot be lifted.