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: 7
Grade code: B7.4.4.2.3
Strand code: 4
Sub-strand code: 4
Content standard code: B7.4.4.2
Indicator code: B7.4.4.2.3
Theme: FORCES AND ENERGY
Subtheme: FORCE AND MOTION
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In everyday life in Ghana, we use machines and tools to make work easier—examples include a wheelbarrow at a building site, a pestle and mortar, a rope and pulley for drawing water, a bottle opener, and a bicycle. Even though machines help us, they do not always give us back all the energy we put in because some is “lost” mainly due to friction. This lesson helps learners understand work input, work output, and efficiency of machines, and how to improve efficiency.
A. Meaning of “Work” in Science (Quick Reminder) In Science, work is done when a force causes an object to move in the direction of the force.
\[ \text{Work (J)}=\text{Force (N)}\times \text{Distance moved (m)} \] Unit of work: joule (J) Example: If you push a box with 20 N and it moves 2 m, then \[ W=20\times 2=40\,J \]
B. Work Input (Energy Put Into the Machine) Work input is the work done on the machine by the user (effort).
\[ \text{Work input} = \text{Effort force} \times \text{Distance moved by effort} \]