Simple Machines

Grade 10 · Physics

Semester 1 | Period 3 | Week 16

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Subject: Physics

Semester: 1

Period: 3

Week: 16

School Name:

Teacher’s Name:

Subject: Physics

Grade Level: Grade 10

Week & Period: Week 16, Period III

Date:

Sub-topic: Simple Machines

Learning Objectives:
By the end of the lesson, learners should be able to:

  1. Identify different types of simple machines.
  2. Define mechanical advantage, velocity ratio, and efficiency.
  3. Solve problems involving these quantities.
  4. Conduct experiments using simple machines.

Instructional Materials:

  • Levers, pulleys, inclined planes
  • Spring balance
  • Load weights
  • Rulers and meter rules
  • Worksheets with diagrams

Anticipation (Warm-Up):
Ask:

  • “Have you used a wheelbarrow, seesaw, or pulley before?”
  • “How do they make your work easier?”

Building Knowledge:

  1. Simple Machines:
    Devices that make work easier by changing the direction or magnitude of force.
    Examples: Lever, Inclined plane, Pulley, Wheel & axle, Screw, Wedge
  2. Mechanical Advantage (MA):
  3. Velocity Ratio (VR):
  4. Efficiency (%):

Solved Example:
A pulley system lifts 40 N using 10 N of effort.

  • MA = 40 ÷ 10 = 4
  • If VR = 5, then Efficiency = (4/5) × 100 = 80%

Experiment:
Title: To determine the mechanical advantage and efficiency of a lever.
Materials: Ruler, spring balance, weights, pivot
Procedure:

  1. Set up a ruler as a lever with a pivot.
  2. Apply load at one end and measure using spring balance.
  3. Apply effort at another point and measure.
  4. Measure distances to calculate VR and MA. Conclusion: Compare calculated values to observe efficiency.

Activities:

  • Set up lever and pulley systems in groups.
  • Calculate MA, VR, and Efficiency using real data.
  • Draw diagrams showing types of levers and their uses.

Assessment:
Oral:

  1. Define mechanical advantage.
  2. Name three simple machines and their uses.

Written:

  1. A load of 50 N is lifted by an effort of 20 N. Find MA.
  2. A machine has MA = 3 and VR = 4. Calculate efficiency.

Homework:

  1. List five household tools that are simple machines and classify them.
  2. What happens to efficiency if friction increases?

Expanded Notes:

  • Simple machines reduce effort but do not reduce total work.
  • Real machines are less than 100% efficient due to energy loss.
  • Apply to daily tools: knife (wedge), staircase (inclined plane)

Differentiation:

  • Peer teaching in group experiments
  • Use large labeled charts for identification
  • Physical demonstration for kinesthetic learners

Teacher’s Reflection:

  • Could learners set up and interpret simple machine systems?
  • Were they able to distinguish between MA and VR?
  • Who needs additional support in applying formulas?