Simple Machine | Jamb(UTME)

Jamb(utme) key points on definition of simple machines; types of machines; mechanical advantages; velocity ratio; efficiency of machines

Definition of Simple Machines

1. A simple machine is a device that makes work easier by multiplying force or changing the direction of force.
2. Simple machines do not have complex moving parts.
3. They work by reducing the effort needed to perform a task.
4. They follow the principle of conservation of energy—no machine can create energy.
5. Examples of simple machines include levers, pulleys, and inclined planes.
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Types of Simple Machines

6. There are six main types of simple machines:
   • Lever
   • Inclined plane
   • Pulley
   • Wheel and axle
   • Wedge
   • Screw
7. Levers consist of a rigid bar that pivots around a fixed point (fulcrum).
8. Inclined planes are sloping surfaces that reduce the effort needed to lift objects.
9. Pulleys use a wheel and rope to lift or move loads more easily.
10. Wheel and axle systems amplify force by using a larger wheel connected to a smaller axle.
11. Wedges are triangular tools used to split, cut, or secure objects.
12. Screws are inclined planes wrapped around a cylinder, used to fasten or lift materials.
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Mechanical Advantage (MA)

13. Mechanical advantage is the ratio of the load (output force) to the effort (input force).
14. The formula for mechanical advantage is:
    $MA = \frac{Load}{Effort}$
15. A higher MA means the machine requires less effort to move a load.
16. For a lever, MA depends on the relative lengths of the effort arm and load arm.
17. In an inclined plane, MA is the ratio of the slope length to the height.
18. For a pulley, MA equals the number of supporting ropes.
19. A mechanical advantage greater than 1 indicates the machine multiplies force.
20. MA is a measure of how much easier a machine makes a task.
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Velocity Ratio (VR)

21. Velocity ratio is the ratio of the distance moved by the effort to the distance moved by the load.
22. The formula for velocity ratio is:
    $VR = \frac{Distance moved by effort}{Distance moved by load}$
23. VR depends only on the design of the machine, not on friction or energy losses.
24. For an inclined plane, VR equals the slope length divided by the height.
25. In a pulley system, VR equals the number of pulleys or ropes used.
26. A machine with a high VR requires less effort to move a load over a greater distance.
27. VR is always greater than or equal to 1 for simple machines.
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Efficiency of Machines

28. Efficiency is the ratio of useful work output to the total work input.
29. The formula for efficiency is:
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    ${Efficiency} = \left( \frac{Useful work output}{Work input} \right) \times 100$
30. Efficiency is expressed as a percentage.
31. Real machines are never 100% efficient due to energy losses like friction and heat.
32. Lubrication can reduce friction and improve a machine’s efficiency.
33. Efficiency depends on the condition of the machine and external factors.
34. A machine with high efficiency converts most input energy into useful output work.
35. Simple machines are generally more efficient than complex machines.
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Applications and Examples

36. Levers are used in crowbars, scissors, and seesaws.
37. Inclined planes are ramps used to move heavy loads with less effort.
38. Pulleys are used in wells, cranes, and elevators.
39. Wheels and axles are found in vehicles, doorknobs, and windmills.
40. Wedges are used in axes, knives, and doorstops.
41. Screws are used in jacks, bolts, and drills.
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Key Relationships

42. Mechanical advantage and velocity ratio are related:
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    ${MA} \leq {VR}$
43. In an ideal machine (no friction):
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    ${MA} = {VR}$
44. Efficiency is calculated by comparing MA and VR:
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    ${Efficiency} = \left( \frac{MA}{VR} \right) \times 100$
45. Lower friction improves efficiency by making MA closer to VR.
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Limitations and Improvements

46. Friction reduces the efficiency of machines.
47. Energy losses due to heat, wear, and deformation affect the performance of machines.
48. Machines should be maintained regularly to maximize efficiency.
49. Adding wheels, lubricants, or smoother surfaces can reduce friction and improve performance.
50. Understanding the principles of simple machines helps in designing efficient tools and systems.
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