Lesson Notes By Weeks and Term v4 - JHS 1
FORCE AND MOTION
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FORCE AND MOTION
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Subject: Science
Class: JHS 1
Term: 3rd Term
Week: 6
Grade code: B7.4.4.2.2
Strand code: 4
Sub-strand code: 4
Content standard code: B7.4.4.2
Indicator code: B7.4.4.2.2
Theme: FORCES AND ENERGY
Subtheme: FORCE AND MOTION
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In our daily life in Ghana, we often need to lift, cut, open, pull out, or move heavy things—lifting a bucket from a well, opening a bottle, cutting plantain, removing a nail from wood, or pushing a wheelbarrow at the farm or market. Many of these tasks become easier because we use levers (simple machines) that help us apply a smaller effort to overcome a bigger load. Understanding the types (classes) of levers and their functions helps learners use tools safely, work efficiently, and solve practical problems at home, school, and in the community.
2.1 Meaning of a Lever A lever is a rigid bar that turns (rotates) about a fixed point to move a load. Parts of a Lever Fulcrum (F): the pivot or turning point (e.g., the screw in scissors). Load (L): the object or resistance to be moved (e.g., the nail being pulled). Effort (E): the force applied to move the load (e.g., your hand force). Important idea: Turning effect (Moment) A force causes turning about a fulcrum. The turning effect is called moment.
\[ \text{Moment} = \text{Force} \times \text{Perpendicular distance from fulcrum} \] The distance from fulcrum to effort is the effort arm. The distance from fulcrum to load is the load arm.
A lever makes work easier by: multiplying force (you use less effort), increasing speed/distance moved, changing the direction of force.
2.2 Classes (Types) of Levers Levers are classified by the relative positions of Fulcrum (F), Load (L), and Effort (E). (A) First-Class Lever (F in the middle) Arrangement: E — F — L *or* L — F — E Key feature: Fulcrum is between effort and load.