Types of Levers and Their Uses | Force and Motion | ORCHIDS
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Force and Motion

Concept: Levers and Their Uses

What is a lever?

Levers are fundamental and simple machines. They are used to working with minimal effort. Every machine is an Examples of a lever.

Parts of a lever:

  • A lever has three parts—the fulcrum, the location where the effort is given, and the location where the load is put.
  • The fulcrum is called the pivot point.
  • In short, we can say that a lever is a rigid bar with a pivot point.

Classification of levers:

Levers can be classified into—

  • Class one/First-class levers.
  • Class two/Second-class levers.
  • Class three/Third-class levers.

1. Class one/First-class levers:

  • First-class levers have a fulcrum (pivot) in the middle.
  • The force is applied at one end, and the weight is located at the other end.
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  • The force is applied in one direction in first-class levers, and the load moves in the opposite direction.
  • The length of the effort arm where the force is applied can be greater, equal, or less than the length of the load arm.

Examples:

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Pliers Scissors Crowbar
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Seesaw Wheel and axle Weighing balance
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Claw and hammer Spoon Tubewell
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How does a first-class lever work?

  • Have you ever tried to open the lid of a can with a screwdriver?
  • When you do that, you have to put effort on the screwdriver's handle at a greater distance than on the load.
  • In this case, the rim of the can be considered the fulcrum situated between the effort and the load.
  • Here, the lid is the load that is nearer to the fulcrum.
  • Since the effort arm is greater than the load arm, we can generate a large force on the load and open the lid.
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2. Class two/Second-class levers:

  • Second class levers have a pivot point (fulcrum) at one side, and effort is put on the other side.
  • The force is applied at one end of the lever, and the weight is located in the middle.
  • In these levers, the load is positioned in the middle.
  • These levers can magnify the effort force because the force is applied at the opposite end of the lever from the fulcrum.
  • In class two levers, the movement of the force and the load are in the same direction.
  • The length of the effort arm is always greater than the length of the load arm.
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Examples:

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Wheelbarrow Hole puncher Bottle opener
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Nutcracker Nail clipper Oar
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How does a second-class lever work?

  • A classic example of a second-class lever is a wheelbarrow.
  • Wheelbarrows are used to lift heavy loads and cross a large distance carrying that load.
  • In the case of a wheelbarrow, the fulcrum is located on the axle and the wheel.
  • The effort can move a large distance to lift a heavy load.
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  • Another example of a second-class lever is bottle openers.
  • The effort arm of the bottle opener is greater than the load arm.
  • Both the effort and the load work in the same direction.
  • The pivot point or fulcrum is located at the end, which opens the bottle cap.
  • With minimal effort, maximum force can be created with the effort arm as it is the largest arm to open the corks and the bottlecaps.
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3. Class two/ Third-class levers:

  • In third-class levers, the effort is located between the load and the fulcrum (pivot).
  • In these levers, the distance moved by the load is always greater than the distance moved by the effort.
  • To make these levers work, one must apply a massive force to the load.
  • All kinds of third-class levers have a mechanical disadvantage.
  • In the case of third-class levers, the input force or the effort is greater than the force produced on the load.
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  • In a third-class lever, the load and the effort always move in the same direction.
  • In all class three levers, the length of the load arm is always greater than the length of the effort arm.
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Fishing rod Broom Bow and arrow
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Baseball bat Tweezers Spade

How does a third-class lever work?

  • The human arm is an example of a third-class lever.
  • When we lift anything using the forearm, we use a class three lever.
  • In the case of a human arm, the elbow is considered the fulcrum.
  • The load is on the hand, and the effort is located between the elbow and the load.
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Pulleys:

  • A pulley is a simple machine. It is used to lift heavy objects.
  • A pulley consists of a wheel that has a grooved track for the rope, chain, or belt to move through it.
  • When a force is applied at one side of the rope or the belt or the chain, it uses the pulley system and moves in a different direction.
  • Pulleys can be of two types—
    •  Fixed pulleys
    •  Movable pulleys

1. Fixed pulleys:

  • The pulley remains attached to a fixed position with a rope on it in the fixed pulley system.
  • These pulleys rotate on their axis at a fixed place.
  • The fixed pulleys change the direction of effort.
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Examples: Flag poles, sail masts, etc.

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2. Movable pulleys:

  • These pulleys do not remain attached to a rigid support.
  • These pulleys are free to move up and down.
  • Movable pulleys remain attached to other objects with the same rope.
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Examples: Construction cranes, elevators, etc.

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New Words:

Effort: It is a kind of force that is exerted by machines.

Fulcrum: It is the location on which the arm of the lever turns.

Rigid: An object is termed rigid when it is unable to bend or not flexible.


Did You Know?

  • Wheel and axle are present in bicycles, sewing machines, coffee beaters, doorknobs, etc.
  • There are many more simple machines except pulleys and levers.
    Examples: An inclined plane is used to lift heavy objects with less force. A screw is also a simple machine that helps to hold things together. A wedge is a simple machine that is used for cutting.
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