A group of students was tasked with creating a simple machine that models a screw. Below is a list of student models and the steps they took to create them. Which of the following models best matches a screw?
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Student A: Takes two popsicle sticks that act as levers and attaches a fulcrum to them to serve as a pivot. At the other end of the fulcrum, two wedges are attached to complete the machine.
Student B: Cuts out a right triangle from a piece of paper to create an inclined plane and wraps it around a pencil
Student C: Folds paper together to create a large conical opening that acts as an inclined plane that sits on top of a hollow tube.
Student D: Cuts out a piece of paper in the shape of a doughnut and puts it on top of straw in the shape of a cylinder. The paper can spin around and functions like a wheel and axle.
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Student C: Folds paper together to create a large conical opening that acts as an inclined plane that sits on top of a hollow tube.
This model best matches a screw because a screw is essentially an inclined plane wrapped around a cylinder. In this model, the conical opening acts as the inclined plane, while the hollow tube represents the cylinder. When the conical opening is turned, it moves along the threads of the tube, just like a screw.
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A screw can be understood as an inclined plane wrapped around a cylinder. When a screw is turned, the threads on the inclined plane (the spiral ridges) move along the stationary cylinder to either raise or lower objects or fasten materials together.
In the model created by Student C, the folded paper forms a large conical shape that acts as an inclined plane. This inclined plane sits on top of a hollow tube (representing the cylinder). When the conical opening is rotated, the inclined plane moves along the tube in a spiral motion, just like how a screw works. This is why the model created by Student C best matches a screw.
Below is a picture of a model catapult made by a student in STEM class. The catapult is a specialized simple machine that includes levers built into the design. Based on the position of the effort (E), fulcrum (F), and load (L) in the picture, which class of lever is the catapult in the image below? *Note, think about the definitions of these terms before selecting a response.
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Class 1 Lever
Class 2 Lever
Class 3 Lever
Class 4 Lever
Based on the positions of the effort (E), fulcrum (F), and load (L) in the picture, the catapult in the image below is a Class 3 Lever. In a Class 3 Lever, the effort is applied between the fulcrum and the load. This arrangement allows for the load to be moved with increased speed or distance compared to the effort applied.
what is the answer
The answer is a Class 3 Lever.
True or false: Simple machines reduce the amount of WORK needed to complete a task?
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True
False
True. Simple machines are designed to make work easier by either increasing the force applied, increasing the distance over which the force is applied, or changing the direction of the applied force. This ultimately reduces the amount of work needed to complete a task.
The following image depicts two types of pulleys. The pulley on the left is a single pulley that has no mechanical advantage. The pulley on the right is a compound pulley that has a mechanical advantage added to it because it has two pulleys. Which of the following statements best describes how these two pulleys work?
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Both the single and compound pulleys change the direction and distance of the force.
Both the single and compound pulleys change the direction of the force but NOT the distance.
Both the single and compound pulleys change the direction of the force but only the compound pulley changes the distance of the force.
Both the single and compound pulleys change the direction of the force but only the simple pulley changes the distance of the force.