Questions and Answers
Which classes of levers are defined as Class 1, Class 2, and Class 3?
What is the characteristic of Class 1 levers?
Fulcrum is in the middle, effort on one side, resistance on the other.
What is the characteristic of Class 2 levers?
Resistance is in the middle.
What is the characteristic of Class 3 levers?
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What is the definition of a lever?
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What does the acronym 'fre, 123' refer to?
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What is the formula for determining the head pressure difference between an intake and an output?
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What should you start with first in the test?
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What are absolutes, and why should you be cautious with them?
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What does the Recall and Comprehend Technical Information section include?
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What does the Recall and Comprehend Verbal and Visual Information involve?
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What is a Gear Train?
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Power = 2pi x Speed (w) x Torque (nm)/60 and Torque = _____ .
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What is a Pulley?
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What is characterized by a Block and Tackle system?
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Study Notes
Classes of Levers
- Three types of levers: Class 1, Class 2, and Class 3 based on the arrangement of fulcrum, effort, and resistance.
Class 1 Levers
- Fulcrum positioned in the middle between effort and resistance.
- Mechanical advantage can be greater or less than 1.
- Examples include seesaws, crowbars, and scissors.
Class 2 Levers
- Resistance is located in the middle, with effort applied on one side and fulcrum on the other.
- Mechanical advantage is always greater than 1.
- Common examples are wheelbarrows, nutcrackers, and car brake pedals.
Class 3 Levers
- Effort is in the middle, resistance is on one side, and fulcrum is on the opposite side.
- Mechanical advantage is always less than 1.
- Examples include tweezers and the human mandible.
Lever Definitions
- A lever is a machine comprising a beam or rigid rod pivoted at a fulcrum.
- Input force is referred to as effort, while output force is termed load or resistance.
"fre, 123" Mnemonic
- Aids in remembering the configuration of levers:
- Class 1: Fulcrum in the middle
- Class 2: Resistance in the middle
- Class 3: Effort in the middle
Head Pressure Formula
- 1 vertical foot equates to 0.433 psi.
- 1 psi corresponds to 2.31 vertical feet.
Overall Test Overview
- 30 minutes to read 2 essays, followed by a 2-hour limit to answer 100 questions.
- Watch 2 videos and answer 20 questions influenced by the content.
- Apply mechanical reasoning across 25 questions focusing on various mechanical concepts.
- Solve 20 mathematical problems covering diverse arithmetic topics.
- Recall technical information through 35 questions based on earlier essays and additional content.
Recommended Starting Subject
- Begin with the Recall and Comprehend Technical Information section, if permissible.
- If not, prioritize solving mathematical questions first.
Caution Against Absolutes
- Be wary of questions using absolutes like "never," "always," or "only."
- Such statements tend to be incorrect or misleading.
Recall Technical Information
- Involves reading essays and answering 35 questions, including some based on essay content.
- Notes are permitted only on the essay packet, not on other test materials.
Verbal and Visual Information Recall
- Consists of 20 questions derived from 2 short videos.
- Each video generates 7-10 questions, with no note-taking allowed during viewing.
Gear Train (Transmission)
- A mechanism of two or more interconnected gears producing mechanical advantage via gear ratios.
Speed, Torque, and Power Relationship
- Power calculation: ( \text{Power} = \frac{2\pi \times \text{Speed (w)} \times \text{Torque (nm)}}{60} )
- Torque calculation: ( \text{Torque} = \frac{60 \times \text{Power (kW)}}{2\pi \times \text{Speed (Rpm)}} )
Belt and Pulley Systems
- Comprise two or more pulleys connected by a belt.
- Mechanical advantage realized when pulleys have differing pitch diameters.
Definition of Pulley
- A pulley is a wheel on an axle designed for supporting movement and directional change of belts or cables.
Rope and Pulley System (Block and Tackle)
- Mechanical advantage is determined by the number of rope segments acting on the load.
- Odd mechanical advantages occur when the anchor knot is at the load; even where it anchors.
- Haul distance can be calculated by multiplying the distance by the mechanical advantage ratio.
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Description
Explore the three classes of levers in physics: Class 1, Class 2, and Class 3. This quiz delves into their definitions, examples, and mechanical advantages. Test your understanding of how these simple machines operate and their practical applications.
