Lever Examples: First, Second, and Third Class Basic Technology JSS 2 Second Term Lesson Notes

(I) Four examples of first-class lever:

1. Seesaw: A seesaw is a classic example of a first-class lever. The fulcrum (pivot point) is located in the middle, with the effort (force applied) on one side and the load (weight being lifted) on the other side. When one end of the seesaw is pushed down, the other end rises, demonstrating how the lever works.
2. Crowbar: A crowbar is another example of a first-class lever. When using a crowbar to lift a heavy object, one end of the crowbar acts as the fulcrum, while the effort is applied at the other end. The load being lifted is situated between the fulcrum and the effort.
3. Scissors: Scissors are a familiar household tool that utilizes a first-class lever mechanism. The fulcrum is located at the pivot point where the two blades meet. When the handles are squeezed together (effort), the blades come together to cut the material (load) placed between them.
4. Nail Clippers: Nail clippers are also an example of a first-class lever. The pivot point acts as the fulcrum, while pressure applied to the handles (effort) causes the blades to come together and trim the nail (load) positioned between them.

(II) Three examples of second-class lever:

1. Wheelbarrow: A wheelbarrow is a classic example of a second-class lever. The wheel serves as the fulcrum, with the load (the contents being carried) located between the fulcrum and the effort (the person pushing or pulling the wheelbarrow). As the handles are lifted, the load is raised, making it easier to transport heavy items.
2. Nutcracker: A nutcracker is another example of a second-class lever. The hinge acts as the fulcrum, with the nut (load) placed between the fulcrum and the effort (the force applied to the handles). As pressure is applied to the handles, the nutcracker exerts force on the nut, cracking it open.
3. Door: A door can also be considered a second-class lever. The hinge serves as the fulcrum, with the load (the weight of the door) situated between the fulcrum and the effort (the force exerted to open or close the door). Pushing or pulling on the door handle applies force, causing the door to swing open or closed.

(III) Three examples of third-class lever:

1. Fishing Rod: A fishing rod is a common example of a third-class lever. The hand holding the rod serves as the fulcrum, with the bait or lure (load) located between the fulcrum and the effort (the force applied by the angler). Casting the fishing line involves applying force to the rod, causing the bait to be propelled forward.
2. Tweezers: Tweezers are another example of a third-class lever. The point where the two arms of the tweezers meet serves as the fulcrum, with the object being grasped (load) situated between the fulcrum and the effort (the force applied by squeezing the tweezers). Squeezing the tweezers applies force, allowing for precise manipulation of small objects.
3. Baseball Bat: A baseball bat can also be considered a third-class lever. The hands holding the bat act as the fulcrum, with the ball (load) positioned between the fulcrum and the effort (the force exerted by swinging the bat). Swinging the bat applies force to the ball, propelling it forward during the game.

Print and Paste on a cardboard:

(I) Four examples of first class lever

(I) Three examples of second class lever

(III) Three examples of third class lever

1. What are levers, and how do they work?
   • Levers are simple machines consisting of a rigid bar (lever arm) that pivots around a fixed point called the fulcrum. They work by applying force to one end of the lever to move a load located at the other end.
2. What are the three classes of levers, and how are they categorized?
   • Levers are categorized into three classes based on the position of the fulcrum relative to the effort and the load. The three classes are first-class, second-class, and third-class levers.
3. Can you provide examples of first-class levers?
   • Yes, examples of first-class levers include seesaws, crowbars, scissors, and nail clippers.
4. How do first-class levers differ from other types of levers?
   • In a first-class lever, the fulcrum is positioned between the effort and the load. This means that the effort and the load are on opposite sides of the fulcrum.
5. What are some real-life applications of second-class levers?
   • Second-class levers are commonly found in tools and equipment designed to lift heavy loads with less effort. Examples include wheelbarrows, nutcrackers, and doors.
6. What distinguishes second-class levers from other types of levers?
   • In a second-class lever, the load is positioned between the fulcrum and the effort. This arrangement allows for greater mechanical advantage when lifting heavy objects.
7. Could you provide examples of third-class levers?
   • Certainly! Examples of third-class levers include fishing rods, tweezers, and baseball bats.
8. How do third-class levers differ from first and second-class levers?
   • In a third-class lever, the effort is applied between the fulcrum and the load. This setup provides greater speed and range of motion but requires more effort to lift the load.
9. Why is it important to understand the different classes of levers?
   • Understanding the classes of levers helps us comprehend how various tools and machines function in our daily lives. It also enables us to design more efficient and effective mechanisms for specific tasks.
10. Can you explain how levers are used in everyday objects and activities?
    • Certainly! Levers are utilized in numerous everyday objects and activities, from using scissors to cut paper to swinging a baseball bat during a game. Understanding how levers work enhances our understanding of the world around us and the technology we interact with daily.

Evaluation

1. A seesaw is an example of a __________ lever. a) first-class b) second-class c) third-class d) fourth-class
2. A crowbar is commonly known as a __________ lever. a) first-class b) second-class c) third-class d) fourth-class
3. Scissors are an example of a __________ lever. a) first-class b) second-class c) third-class d) fourth-class
4. Nail clippers demonstrate the mechanics of a __________ lever. a) first-class b) second-class c) third-class d) fourth-class
5. A wheelbarrow is an example of a __________ lever. a) first-class b) second-class c) third-class d) fourth-class
6. Nutcrackers operate as a __________ lever. a) first-class b) second-class c) third-class d) fourth-class
7. Doors can be classified as __________ levers. a) first-class b) second-class c) third-class d) fourth-class
8. Fishing rods are commonly categorized as __________ levers. a) first-class b) second-class c) third-class d) fourth-class
9. Tweezers function as __________ levers. a) first-class b) second-class c) third-class d) fourth-class
10. Baseball bats are often referred to as __________ levers. a) first-class b) second-class c) third-class d) fourth-class
11. In a first-class lever, the fulcrum is positioned between the __________ and the load. a) effort b) load c) resistance d) power
12. Second-class levers have the load located between the fulcrum and the __________. a) effort b) load c) resistance d) power
13. Third-class levers have the effort applied between the fulcrum and the __________. a) effort b) load c) resistance d) power
14. The seesaw is a classic example of a __________ lever. a) first-class b) second-class c) third-class d) fourth-class
15. Tweezers are an example of a __________ lever. a) first-class b) second-class c) third-class d) fourth-class