Solving Simple Problems on Work, Energy, Time, and Speed

Grade 6 · General Science

Semester 2 | Period 5 | Week 28

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Subject: General Science

Semester: 2

Period: 5

Week: 28

School Name:
Teacher’s Name:
Subject: General science
Grade Level: Grade 6
Date: Week 28
Lesson Duration: 45 minutes
Week & Period: Week 28, Period 5
Topic: Solving Simple Problems on Work, Energy, Time, and Speed
Sub-topic: Work problems, energy problems, speed problems, word problems with practical examples
Learning Objectives
By the end of the lesson, students should be able to solve basic problems involving work, energy, time, and speed using appropriate formulas and interpret results in practical contexts.

Previous Knowledge
Students already know the formulas for work (Work = Force × Distance), speed (Speed = Distance ÷ Time), and basic concepts of energy.

Instructional Materials
Worksheets with sample problems, calculators, chart paper, markers, objects for demonstrations.

Lesson Development – ABC Model
A – Anticipation (Warm-up / Starter)
Time: 5–10 minutes
Ask learners to recall formulas for work, speed, and energy. Give a simple scenario: “If you push a box 2 meters with a force of 10 N, what is the work done?”

B – Building Knowledge (Main Lesson Body)

Time: 25–30 minutes

Learners’ Activities (Expanded):

  • Students work in pairs to solve guided examples on work, energy, and speed.
  • Teacher demonstrates step-by-step how to calculate:
    • Work (Work = Force × Distance)
    • Speed (Speed = Distance ÷ Time)
    • Kinetic Energy (KE = ½ × mass × velocity²)
    • Potential Energy (PE = mass × gravity × height, with g = 9.8 m/s² or 10 m/s² for simplicity).
  • Learners practice with real-life scenarios such as:
  1. Lifting a bucket of water.
  2. A runner covering a certain distance.
  3. A book raised to a shelf.
  • Students solve word problems on the board, explain their reasoning steps, and check each other’s answers.
  • Teacher emphasizes correct unit usage (Joules for work/energy, m/s for speed, N for force).

Assessment Checks:

  1. Learners solve a sample problem on the board:
    • If a force of 20 N moves a box 5 m, how much work is done?
      • Solution: Work = 20 × 5 = 100 J.
  1. Teacher asks: What is the formula for kinetic energy? Learners respond: ½ × mass × velocity².
  2. Peer correction: Students swap answers and check for correct substitution and unit use.
  3. Teacher asks learners to explain the difference between potential and kinetic energy in their own words.

Notes (Expanded & Detailed):

  • Work is done when a force moves an object over a distance.
    • Formula: W = F × d
    • Unit: Joule (J)
    • Example: Carrying a 10 N load over 3 m → W = 10 × 3 = 30 J.
  • Speed tells how fast an object moves.
    • Formula: Speed = Distance ÷ Time
    • Example: A boy runs 100 m in 20 seconds → Speed = 100 ÷ 20 = 5 m/s.
  • Kinetic Energy (KE): Energy of motion.
    • Formula: KE = ½ × m × v²
    • Example: A 2 kg ball moving at 3 m/s → KE = ½ × 2 × 3² = 9 J.
  • Potential Energy (PE): Stored energy due to position.
    • Formula: PE = m × g × h
    • Example: A 5 kg box lifted 2 m high → PE = 5 × 10 × 2 = 100 J.
  • Key Difference:
    • KE = moving objects.
    • PE = stored in objects raised or stretched.

Extra Practice / Assignment:

  • Classwork: Solve 3 short problems on work, KE, and PE.
  • Homework:
  1. A 1.5 kg book is lifted 2 m. Find its potential energy.
  2. A runner of mass 40 kg runs at 5 m/s. Find his kinetic energy.
  3. If a force of 15 N pushes a chair 4 m, how much work is done?

C – Consolidation (Conclusion & Assessment)
Time: 5–10 minutes
Summary: Recap formulas and methods for solving work, energy, time, and speed problems. Highlight common errors and strategies to avoid them.

Evaluation Method (Expanded)
Exit slip/quiz: Solve a given problem involving work, speed, or energy. Teacher collects slips and provides oral feedback.
Assignment (Expanded): Complete a set of word problems from the textbook involving work, energy, and speed.
Follow-up Activity: Observe an activity at home (lifting, walking, or running) and calculate work or speed involved.
Differentiation / Inclusive Strategies: Provide step-by-step worked examples, allow peer collaboration, and offer simplified problems for learners needing extra support.