
Chapter Summary for MCQ: Simple Machines
πΉ 1. What is a Simple Machine?
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A simple machine is a device that makes our work easier by changing the direction or magnitude of force.
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It does not multiply energy, only redistributes or redirects it.
πΉ 2. Types of Simple Machines
There are six basic types:
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Lever β e.g., seesaw, scissors
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Inclined Plane β e.g., ramp
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Pulley β e.g., flagpole, well
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Wheel and Axle β e.g., steering wheel
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Wedge β e.g., knife, axe
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Screw β e.g., jar lid, drill
πΉ 3. Lever and Its Classes
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A lever is a rigid bar that pivots around a fixed point (fulcrum).
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Three classes:
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Class I: Fulcrum in the middle (e.g., scissors)
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Class II: Load in the middle (e.g., wheelbarrow)
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Class III: Effort in the middle (e.g., tongs)
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πΉ 4. Key Terms
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Load (L): The object to be moved.
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Effort (E): Force applied to move the load.
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Fulcrum (F): Pivot point of a lever.
πΉ 5. Mechanical Advantage (MA)
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Ratio of load to effort:
MA=LoadEfforttext{MA} = frac{text{Load}}{text{Effort}}
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MA > 1: Less effort needed
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MA = 1: Just changes direction
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MA < 1: More effort needed (e.g., speed gain)
πΉ 6. Velocity Ratio (VR)
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Ratio of distance moved by effort to distance moved by load:
VR=DistanceΒ byΒ EffortDistanceΒ byΒ Loadtext{VR} = frac{text{Distance by Effort}}{text{Distance by Load}}
πΉ 7. Efficiency (%)
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How effectively a machine works:
Efficiency=(MAVR)Γ100text{Efficiency} = left( frac{text{MA}}{text{VR}} right) times 100
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Efficiency is always less than 100% due to friction and energy loss.
πΉ 8. Pulley System
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A fixed pulley changes the direction of force (VR = 1).
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A movable pulley reduces effort (MA > 1).
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In a combination pulley, VR and MA depend on the number of ropes supporting the load.
πΉ 9. Inclined Plane
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An inclined surface used to raise heavy objects.
text{MA} = frac{text{Length of slope}}{text{Height of slope}}
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π§ MCQ Focus Points
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Know all machine types with examples.
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Be clear on MA, VR, and efficiency formulas.
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Identify lever classes by positions of load, effort, and fulcrum.
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Understand direction change vs. force gain in pulleys and levers.
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Recognise real-life applications of each type.
π You Can Also Read:
- β MCQ Quiz: Simple Machine
- π’ Numerical-Based MCQ β Simple Machine
- π§ Conceptual MCQs: Friction
- π MCQ Quiz: Friction
- π MCQ Quiz: Motion
- π§ Conceptual & Numerical MCQs: Motion
- Β Unit and Dimension
- π Scalar and Vector
- Use of Fundamental Units in Physical Equations to Examine Their Homogeneity
- Class β 10 (Science and Technology)
- Β full text documents, including the curriculum, CDC eLibrary