Mechanics and Thermal Physics

Introduction to Physics - Meaning of Physics as a science
Introduction to Physics - Branches of Physics

By the end of the lesson, the learner should be able to:

- Define Physics as a branch of science
- Explain why Physics is considered a science
- Relate Physics to everyday observations like vehicle movement and electrical appliances

Discuss in groups the meaning of Physics using textbooks and digital resources
- Search for the meaning of Physics as a branch of science
- Share explanations on the meaning of Physics with classmates

What is Physics and why is it considered a science?

- Digital resources
- Charts showing branches of Physics

- Oral questions - Group discussions - Observation

Mechanics and Thermal Physics

Introduction to Physics - Importance of Physics in day-to-day life

-List applications of Physics in everyday life
- Categorize Physics applications in transportation, communication, medicine and home appliances
- Recognize how Physics enables technologies like GPS, microwave ovens and digital cameras

-Search and list examples of Physics applications in everyday life
- Organize examples into categories such as transportation, communication, medicine and home appliances
- Discuss significance of Physics applications in modern technology

How does Physics contribute to modern technology and daily conveniences?

- Pictures of technological devices
- Digital resources

- Group presentations - Oral questions - Written tests

Mechanics and Thermal Physics

Introduction to Physics - Relationship with other fields and careers
Pressure - Atmospheric pressure as used in Physics

-Explain relationships between Physics and other subjects like Geography, Chemistry and Mathematics
- Identify career opportunities in Physics
- Connect Physics knowledge to career paths in engineering, medicine, research and education

-Research and identify fields related to Physics
- Discuss how Physics relates to Geography, Mathematics, Chemistry, History and Technology
- Design career charts highlighting Physics-related careers
- Engage resource persons on career opportunities

What career paths can Physics knowledge open for you?

- Charts and manila papers
- Balloon, glass, water, manila paper
- Digital resources

- Career chart presentations - Oral questions - Written assignments

Mechanics and Thermal Physics

Pressure - Demonstrating atmospheric pressure effects

- Perform experiments to show atmospheric pressure exists
- Explain observations from atmospheric pressure experiments
- Connect atmospheric pressure to crushing can experiment and weather phenomena

-Pour hot water into plastic bottle and observe deformation when cooled
- Perform balloon in bottle experiment with hole at point B
- Discuss role of atmospheric pressure in each experiment

Why does a plastic bottle crush when hot water inside it cools?

- Plastic bottles, hot water, cold water
- Balloon, optical pin, sellotape

- Practical reports - Observation - Oral questions

Mechanics and Thermal Physics

Pressure - Factors affecting pressure in liquids
Pressure - Investigating pressure variation with depth

Identify factors affecting pressure in liquids
- Investigate relationship between pressure, depth and density
- Relate liquid pressure to swimming pool depth and dam construction

- Use U-tube and thistle funnel to investigate pressure variation with depth
- Lower thistle funnel to different depths and note U-tube readings
- Repeat with brine and glycerine to compare densities

How do depth and density affect pressure in liquids?

- U-tube, rubber tubing, thistle funnel
- Retort stand, water, brine, glycerine
- Tin, sellotape, nail, hammer
- Water, brine, ruler

- Practical observation - Data recording - Oral questions

Mechanics and Thermal Physics

Pressure - Deriving and applying P = ρgh

-Derive the pressure formula P = ρgh
- Apply the formula to calculate pressure in liquids
- Use the formula to solve real-world problems like calculating pressure at ocean depths

-Derive pressure formula from first principles using weight, volume and density
- Discuss mathematical relationship between pressure, density, gravity and depth
- Solve numerical problems using P = ρgh

How do we calculate pressure at any depth in a liquid?

- Scientific calculators
- Worked examples

- Numerical exercises - Written tests - Problem solving

Mechanics and Thermal Physics

Pressure - Solving pressure problems using P = ρgh

-Calculate pressure at various depths in different liquids
- Determine total pressure including atmospheric pressure
- Apply calculations to real situations like diving depths and water storage tanks

-Solve problems involving barometer construction
- Calculate pressure exerted by water at bottom of tanks
- Determine force on tap openings using pressure formula
- Work out total pressure at various depths

How do divers experience increased pressure at greater depths?

- Scientific calculators
- Problem worksheets

- Written exercises - Class work - Oral questions

Mechanics and Thermal Physics

Pressure - Pascal's principle and transmission of pressure

- Explain Pascal's principle of pressure transmission
- Demonstrate transmission of pressure using syringes
- Connect Pascal's principle to hydraulic systems in vehicles and machines

-Connect two syringes with rubber tubing filled with water
- Push plunger of one syringe and observe effect on the other
- Discuss how pressure is transmitted equally in enclosed fluids

How is pressure transmitted through fluids in a closed system?

- Two syringes (different sizes)
- Rubber tubing, water

- Practical observation - Oral questions - Written tests

Mechanics and Thermal Physics

Pressure - Hydraulic lift and brake systems

-Explain how hydraulic lift works
- Calculate force multiplication in hydraulic systems
- Relate hydraulic principles to car jacks and lifting equipment

- Study hydraulic lift diagram and identify components
- Derive relationship between force, pressure and area in hydraulic systems
- Solve numerical problems on hydraulic lift
- Discuss advantages of hydraulic systems

How do hydraulic lifts multiply force to lift heavy loads?

- Hydraulic lift diagrams
- Scientific calculators

- Numerical problems - Written tests - Oral questions

Mechanics and Thermal Physics

Pressure - Hydraulic lift and brake systems

-Explain how hydraulic lift works
- Calculate force multiplication in hydraulic systems
- Relate hydraulic principles to car jacks and lifting equipment

- Study hydraulic lift diagram and identify components
- Derive relationship between force, pressure and area in hydraulic systems
- Solve numerical problems on hydraulic lift
- Discuss advantages of hydraulic systems

How do hydraulic lifts multiply force to lift heavy loads?

- Hydraulic lift diagrams
- Scientific calculators

- Numerical problems - Written tests - Oral questions

Mechanics and Thermal Physics

Pressure - Car hydraulic braking system

-Identify parts of hydraulic brake system
- Explain how hydraulic brakes work
- Relate brake system knowledge to road safety and vehicle maintenance

-Study diagram of hydraulic braking system
- Identify functions of brake pedal, master cylinder, slave cylinder, brake fluid
- Visit nearby garage to observe braking system
- Discuss properties of brake fluid

Why do car brakes fail when air enters the brake pipes?

- Hydraulic brake diagrams
- Resource persons (mechanics)

- Oral questions - Written assignments - Field visit reports

Mechanics and Thermal Physics

Pressure - Drinking straw and syringe applications

-Explain how drinking straw works using atmospheric pressure
- Describe the working principle of a syringe
- Apply knowledge to medical applications and everyday drinking

- Suck water through straw and observe what happens
- Make hole in straw and repeat experiment
- Demonstrate syringe operation by drawing and expelling water
- Discuss pressure differences that enable these devices to work

Why can't you drink through a straw with a hole in it?

- Straws, syringes
- Glass, water, optical pin

- Practical demonstrations - Oral questions - Written tests

Mechanics and Thermal Physics

Pressure - Siphoning principle and applications

-Demonstrate siphoning process
- Explain conditions for continuous siphoning
- Apply siphoning knowledge to fuel transfer and aquarium maintenance

-Set up siphon using two containers at different heights
- Fill tube with water and demonstrate siphoning
- Identify conditions for continuous flow
- Calculate pressure difference in siphon system

Under what conditions does a siphon work continuously?

- Plastic/rubber tube
- Two containers, water

- Practical observation - Oral questions - Written reports

Mechanics and Thermal Physics

Pressure - Siphoning principle and applications

-Demonstrate siphoning process
- Explain conditions for continuous siphoning
- Apply siphoning knowledge to fuel transfer and aquarium maintenance

-Set up siphon using two containers at different heights
- Fill tube with water and demonstrate siphoning
- Identify conditions for continuous flow
- Calculate pressure difference in siphon system

Under what conditions does a siphon work continuously?

- Plastic/rubber tube
- Two containers, water

- Practical observation - Oral questions - Written reports

Mechanics and Thermal Physics

Pressure - Pumping mechanisms

-Explain working of bicycle pump
- Describe operation of lift pump
- Enjoy relating pump mechanisms to inflating tyres and drawing water from wells

- Examine bicycle pump and identify leather washer function
- Demonstrate upstroke and downstroke of bicycle pump
- Study lift pump diagram and explain valve operations
- Discuss limitations of lift pump (10m height limit)

How does a bicycle pump use atmospheric pressure to inflate tyres?

- Bicycle pump
- Lift pump diagrams

- Practical demonstrations - Oral questions - Written tests

Mechanics and Thermal Physics

Mechanical Properties - Types of mechanical properties

-Define mechanical properties of materials
- Identify different types of materials and their properties
- Connect material properties to selection of materials for tools like axes and hammers

-Discuss meaning of materials and types (metals, wood, plastics, glass)
- Search for properties: ductility, malleability, elasticity, brittleness, strength, hardness, stiffness
- Relate properties to everyday materials

Why are different materials used for different purposes?

- Samples of different materials
- Digital resources

- Oral questions - Group discussions - Written assignments

Mechanics and Thermal Physics

Mechanical Properties - Demonstrating ductility, brittleness and malleability

-Demonstrate ductility, brittleness and malleability
- Classify materials based on their mechanical behavior
- Apply knowledge to explain why copper is used for wires and glass breaks easily

-Use G-clamp to fix metal rods and apply loads until bending or breaking
- Hammer iron nail and observe flattening
- Compare behavior of glass, wood, lead, copper and steel rods
- Classify materials as ductile, brittle or malleable

Why does glass break suddenly while copper bends without breaking?

- G-clamp, metal rods, hammer
- Nails, glass rod, masses

- Practical observation - Classification tables - Written tests

Mechanics and Thermal Physics

Mechanical Properties - Demonstrating ductility, brittleness and malleability

-Demonstrate ductility, brittleness and malleability
- Classify materials based on their mechanical behavior
- Apply knowledge to explain why copper is used for wires and glass breaks easily

-Use G-clamp to fix metal rods and apply loads until bending or breaking
- Hammer iron nail and observe flattening
- Compare behavior of glass, wood, lead, copper and steel rods
- Classify materials as ductile, brittle or malleable

Why does glass break suddenly while copper bends without breaking?

- G-clamp, metal rods, hammer
- Nails, glass rod, masses

- Practical observation - Classification tables - Written tests

Mechanics and Thermal Physics

Mechanical Properties - Elasticity and hardness

Demonstrate elasticity using springs and rubber bands
- Test hardness of different materials
- Relate elasticity to shock absorbers and hardness to cutting tools

- Stretch springs and rubber bands and observe return to original shape
- Use sharp object to mark different materials and compare hardness
- Classify materials as elastic or hard
- Discuss applications of elastic and hard materials

Why do springs return to their original shape after stretching?

- Springs, rubber bands
- Nail, various material samples

- Practical demonstrations - Oral questions - Written assignments

Mechanics and Thermal Physics

Mechanical Properties - Investigating Hooke's Law

-State Hooke's Law in physics
- Investigate relationship between force and extension
- Enjoy applying Hooke's Law to weighing scales and spring balances

-Set up spiral spring with pointer and metre rule
- Add masses in steps and record extensions
- Calculate force for each mass
- Record data in table and observe pattern

What is the relationship between stretching force and extension of a spring?

- Spiral spring, retort stand
- Masses, metre rule

- Data recording - Practical reports - Oral questions

Mechanics and Thermal Physics

Mechanical Properties - Graphical analysis and spring constant

-Plot force-extension graph
- Determine spring constant from graph gradient
- Use spring constant to predict extension for given forces

-Plot graph of force against extension
- Determine gradient of straight line
- Identify spring constant from graph
- Discuss elastic limit and plastic deformation

How do we determine the spring constant of a spiral spring?

- Graph papers
- Data from previous experiment
- Scientific calculators

- Graph plotting - Gradient calculation - Written tests

Mechanics and Thermal Physics

Mechanical Properties - Combined spring constant

-Determine combined spring constant for springs in series
- Determine combined spring constant for springs in parallel
- Apply knowledge to vehicle suspension systems with multiple springs

-Connect two identical springs in series and determine combined spring constant
- Connect same springs in parallel and determine combined spring constant
- Compare combined constants with single spring constant
- Derive formulae for series and parallel combinations

Why is the combined spring constant different for series and parallel arrangements?

- Two identical springs
- Retort stand, masses
- Metre rule

- Practical observation - Numerical problems - Written tests

Mechanics and Thermal Physics

Mechanical Properties - Combined spring constant

-Determine combined spring constant for springs in series
- Determine combined spring constant for springs in parallel
- Apply knowledge to vehicle suspension systems with multiple springs

-Connect two identical springs in series and determine combined spring constant
- Connect same springs in parallel and determine combined spring constant
- Compare combined constants with single spring constant
- Derive formulae for series and parallel combinations

Why is the combined spring constant different for series and parallel arrangements?

- Two identical springs
- Retort stand, masses
- Metre rule

- Practical observation - Numerical problems - Written tests

Mechanics and Thermal Physics

Mechanical Properties - Hooke's Law in car shock absorbers

-Explain application of Hooke's Law in shock absorbers
- Describe how suspension systems work
- Relate overloading of vehicles to damage of shock absorbers

-Research application of Hooke's Law in car shock absorbers
- Discuss how shock absorbers compress and extend
- Explain damping effect in suspension systems
- Discuss effects of overloading on vehicle springs

How do shock absorbers provide a smooth ride on bumpy roads?

- Shock absorber diagrams
- Digital resources

- Oral questions - Written assignments - Research presentations

Mechanics and Thermal Physics

Mechanical Properties - Tensile stress and strain

-Define tensile stress and tensile strain
- Calculate stress and strain using formulae
- Apply stress-strain concepts to engineering structures like bridges and buildings

-Discuss meaning of tensile stress (Force/Area) and tensile strain (extension/original length)
- Derive formula for stress and strain
- Solve numerical problems involving stress and strain

Why is stress measured in N/m² while strain has no units?

- Scientific calculators
- Worked examples

- Numerical exercises - Written tests - Oral questions

Mechanics and Thermal Physics

Mechanical Properties - Young's Modulus determination

-Define Young's Modulus
- Calculate Young's Modulus from stress and strain
- Interpret stress-strain graphs for material selection in construction

-Derive Young's Modulus as ratio of stress to strain
- Plot stress-strain graph and identify regions
- Identify elastic limit, yield point and breaking point
- Solve problems involving Young's Modulus

What does the stress-strain graph tell us about material behavior?

- Graph papers
- Scientific calculators

- Graph interpretation - Numerical problems - Written tests

Mechanics and Thermal Physics

Mechanical Properties - Young's Modulus determination

-Define Young's Modulus
- Calculate Young's Modulus from stress and strain
- Interpret stress-strain graphs for material selection in construction

-Derive Young's Modulus as ratio of stress to strain
- Plot stress-strain graph and identify regions
- Identify elastic limit, yield point and breaking point
- Solve problems involving Young's Modulus

What does the stress-strain graph tell us about material behavior?

- Graph papers
- Scientific calculators

- Graph interpretation - Numerical problems - Written tests

Mechanics and Thermal Physics

Mechanical Properties - Industrial applications

-Describe industrial applications of mechanical properties
- Select appropriate materials for specific applications
- Apply material selection principles to everyday items like scissors, springs and brake pads

-Research applications in manufacturing, automobile and construction industries
- Discuss material selection for bridges, wires, cutting tools
- Identify properties required for various products
- Present findings on importance of mechanical properties

Why do engineers study mechanical properties before selecting materials?

- Digital resources
- Sample products (springs, wires, tools)

- Presentations - Oral questions - Written assignments

Mechanics and Thermal Physics

Temperature and Thermal Expansion - Meaning of temperature
Temperature and Thermal Expansion - Temperature conversion

-Define temperature as a measure of degree of hotness or coldness
- Identify the SI unit of temperature and other units
- Relate temperature measurement to everyday activities like cooking and weather forecasting

-Discuss with peers the meaning of temperature
- Carry out activities to demonstrate hotness and coldness using water at different temperatures
- Use digital resources to search for temperature units and conversion formulas

How do we measure the degree of hotness or coldness of a body?

- Bowls of water at different temperatures
- Digital resources
- Scientific calculators

- Oral questions - Observation - Written assignments

Mechanics and Thermal Physics

Temperature and Thermal Expansion - Liquid-in-glass thermometers

-Identify parts of a liquid-in-glass thermometer
- Describe the working principle of alcohol-in-glass thermometer
- Relate liquid-in-glass thermometers to medical and laboratory temperature measurements

- Identify and draw liquid-in-glass thermometer and label its parts
- Measure temperature of water at different temperatures using alcohol thermometer
- Discuss advantages and limitations of alcohol thermometers

How does liquid expansion help in measuring temperature?

- Alcohol-in-glass thermometer
- Beakers with water
- Heat source

- Practical assessment - Observation - Oral questions

Mechanics and Thermal Physics

Temperature and Thermal Expansion - Clinical thermometer
Temperature and Thermal Expansion - Thermocouple thermometer

- Identify features of a clinical thermometer
- Explain the function of the constriction in clinical thermometers
- Connect clinical thermometer use to healthcare and disease diagnosis

-Draw and label parts of a clinical thermometer
- Measure body temperature using a clinical thermometer
- Discuss why clinical thermometers have constrictions

Why does a clinical thermometer have a constriction?

- Clinical thermometer
- Antiseptic
- Cotton wool
- Thermocouple with voltmeter
- Heat source
- Melting ice

- Practical assessment - Oral questions - Written tests

Mechanics and Thermal Physics

Temperature and Thermal Expansion - RTDs and thermistors
Temperature and Thermal Expansion - Infrared and bimetallic thermometers

Explain how resistance changes with temperature in RTDs
- Differentiate between RTDs and thermistors
- Connect RTDs and thermistors to modern digital thermometers and electronic devices

-Use digital resources to search for information on RTDs and thermistors
- Compare RTD and thermistor thermometers
- Discuss applications in modern electronics

How does electrical resistance help in measuring temperature?

- Digital thermometer
- Digital resources
- Infrared thermometer
- Bimetallic thermometer
- Various surfaces

- Oral questions - Written assignments - Group presentations

Mechanics and Thermal Physics

Temperature and Thermal Expansion - Expansion in solids

-Demonstrate thermal expansion in solids using ball and ring apparatus
- Explain why solids expand when heated
- Connect thermal expansion to why tight jar lids loosen when heated

-Carry out activities using ball and ring apparatus to demonstrate expansion
- Discuss particle theory explanation for expansion
- Record observations and draw conclusions

Why does a heated ball fail to pass through a ring it passed through when cold?

- Ball and ring apparatus
- Heat source
- Safety equipment

- Practical assessment - Observation - Written questions

Mechanics and Thermal Physics

Temperature and Thermal Expansion - Linear expansivity

By the end of the lesson, the learner should be able to:

- Define linear expansivity
- Calculate change in length using the linear expansion formula
- Relate linear expansivity to expansion gaps in railway tracks and bridges

In groups, learners are guided to:
- Measure initial and final lengths of heated metal rods
- Calculate linear expansivity from experimental data
- Apply the formula ΔL = αL₀Δθ to solve problems

How does the type of material affect its expansion?

- Metal rods (iron, copper, aluminium)
- Heat source
- Ruler/measuring tape

- Written tests - Practical assessment - Problem-solving exercises

Mechanics and Thermal Physics

Temperature and Thermal Expansion - Expansion in liquids

By the end of the lesson, the learner should be able to:

- Demonstrate thermal expansion in liquids
- Explain why the liquid level first falls then rises when heated
- Connect liquid expansion to the working of liquid-in-glass thermometers

In groups, learners are guided to:
- Set up apparatus with flask, tube and coloured water
- Heat the flask and observe liquid level changes
- Discuss why flask expands before liquid

Why does the liquid level initially fall before rising when heated?

- Round-bottomed flask
- Narrow tube with cork
- Coloured water
- Heat source

- Practical assessment - Observation - Oral questions

Mechanics and Thermal Physics

Temperature and Thermal Expansion - Anomalous expansion of water

-Explain the anomalous expansion of water between 0°C and 4°C
- Describe why ice floats on water
- Connect anomalous expansion to survival of aquatic life in frozen lakes during winter

-Use digital resources to research anomalous expansion of water
- Discuss the density-temperature graph of water
- Explain formation of ice on water surfaces

Why does ice float on water?

- Digital resources
- Charts showing density vs temperature
- Reference books

- Oral questions - Written assignments - Group discussions

Mechanics and Thermal Physics

Temperature and Thermal Expansion - Applications in daily life

-Describe applications of thermal expansion in bridges and railways
- Explain the working of bimetallic strips in thermostats
- Connect thermal expansion to car indicator systems, electric kettles and fire alarms

-Discuss expansion joints in bridges and railways
- Explain working of bimetallic strip in thermostats
- Use digital resources to search for applications of thermal expansion

How do engineers account for thermal expansion in construction?

- Pictures of expansion joints
- Bimetallic strip
- Digital resources

- Written tests - Oral questions - Project work

Mechanics and Thermal Physics

Moments and Equilibrium - Centre of gravity of regular objects

- Define centre of gravity
- Determine the C.O.G of regular shaped objects (square, rectangle, circle)
- Relate centre of gravity to balancing objects on fingertips

-Use balancing method to find C.O.G of regular cut-outs
- Use geometrical construction (diagonals) to locate C.O.G
- Compare results from both methods

Where is the centre of gravity of a square located?

- Cut-out shapes (square, rectangle, circle)
- Pencil for balancing
- Ruler

- Practical assessment - Observation - Oral questions

Mechanics and Thermal Physics

Moments and Equilibrium - Centre of gravity of triangles

-Determine C.O.G of triangular objects using medians
- Locate C.O.G at intersection of medians
- Apply knowledge of C.O.G to understanding stability of triangular structures

-Cut out triangular shapes from cardboard
- Construct medians and mark intersection point
- Verify C.O.G by balancing on pencil tip

How do we find the centre of gravity of a triangle?

- Triangular cut-outs
- Ruler
- Pencil
- Marker

- Practical assessment - Written questions - Observation

Mechanics and Thermal Physics

Moments and Equilibrium - Centre of gravity of irregular objects
Moments and Equilibrium - Stable equilibrium

-Determine C.O.G of irregular objects using plumb line method
- Explain why suspended objects align with C.O.G below pivot
- Connect plumb line method to levelling tools used in construction

-Suspend irregular lamina from different points
- Use plumb line to draw vertical lines
- Mark intersection as C.O.G and verify by balancing

Why do all vertical lines through suspension points meet at one point?

- Irregular cardboard shapes
- String and small weight (plumb line)
- Stand and clamp
- Marker
- Cone-shaped objects
- Flat surface

- Practical assessment - Observation - Written tests

Mechanics and Thermal Physics

Moments and Equilibrium - Unstable and neutral equilibrium

-Demonstrate unstable equilibrium using cone on its tip
- Demonstrate neutral equilibrium using cone on its side
- Connect equilibrium states to why loaded trucks are more stable than empty ones

-Balance cone on tip and observe behavior when pushed
- Place cone on its side and push slightly
- Compare all three states of equilibrium

Why does a cone on its tip topple when slightly pushed?

- Cone-shaped objects
- Spherical ball
- Flat surface

- Practical assessment - Observation - Written questions

Mechanics and Thermal Physics

Moments and Equilibrium - Factors affecting stability
Moments and Equilibrium - Turning effect of a force

-Investigate effect of base area on stability
- Investigate effect of position of C.O.G on stability
- Connect stability factors to why buses have luggage compartments underneath

-Compare stability of bottles with different amounts of sand
- Compare stability of books resting on different surfaces
- Discuss how to increase stability of objects

How does the position of centre of gravity affect stability?

- Plastic bottles
- Sand
- Door
- Spring balance
- Ruler

- Practical assessment - Oral questions - Written tests

Mechanics and Thermal Physics

Moments and Equilibrium - Calculating moments

-Calculate moment of a force using Moment = Force × perpendicular distance
- State the SI unit of moment
- Apply moment calculations to using spanners to loosen tight bolts

-Apply forces at different distances from pivot
- Calculate moments from experimental data
- Solve numerical problems on moments

How does increasing distance from pivot affect the turning effect?

- Ruler on pivot
- Spring balance
- Known weights
- Metre rule

- Written tests - Problem-solving exercises - Practical assessment

Mechanics and Thermal Physics

Moments and Equilibrium - Verifying principle of moments

-State the principle of moments
- Verify principle of moments experimentally
- Connect principle of moments to balancing on see-saws

-Set up metre rule on pivot with weights on both sides
- Adjust positions until balanced
- Calculate and compare clockwise and anticlockwise moments

When is a body in rotational equilibrium?

- Metre rule
- Knife edge pivot
- Known masses
- String

- Practical assessment - Written tests - Observation

Mechanics and Thermal Physics

Moments and Equilibrium - Applications of principle of moments

- Apply principle of moments to solve problems
- Determine unknown forces using principle of moments
- Use principle of moments to calculate where children should sit on a see-saw to balance

- Solve problems involving balanced beams
- Calculate unknown masses and distances
- Discuss applications in beam balances and levers

How can we use moments to find an unknown mass?

- Scientific calculators
- Problem sheets
- Beam balance

- Written tests - Problem-solving exercises - Oral questions

Mechanics and Thermal Physics

Moments and Equilibrium - Determining mass using moments

- Determine mass of a metre rule using principle of moments
- Locate C.O.G of a metre rule experimentally
- Apply the method to weighing objects using simple beam balances

-Suspend metre rule and find balance point
- Use known mass to determine mass of rule
- Apply principle of moments in calculations

How can we determine the mass of a ruler using moments?

- Metre rule
- Stand and thread
- Known masses (50g, 100g)

- Practical assessment - Written tests - Problem-solving

Mechanics and Thermal Physics

Moments and Equilibrium - Parallel forces and two supports

- Demonstrate moments about two points of support
- Apply conditions for equilibrium with parallel forces
- Connect parallel forces to how bridges distribute weight across supports

-Set up metre rule supported by two spring balances
- Attach weights at different positions
- Verify sum of upward forces equals sum of downward forces

How are forces distributed in a beam supported at two points?

- Metre rule
- Two spring balances
- Known weights
- Stand

- Practical assessment - Written tests - Observation

Mechanics and Thermal Physics

Moments and Equilibrium - Couple and torque

- Define a couple as two equal and opposite parallel forces
- Calculate torque as Force × perpendicular distance between forces
- Connect couples to turning steering wheels and opening bottle caps

-Demonstrate couple using a plank fixed at centre
- Apply equal forces in opposite directions
- Calculate torque from experimental data

Why do we need two hands to turn a steering wheel smoothly?

- Uniform plank with central pivot
- Spring balances
- Steering wheel model

- Practical assessment - Written tests - Oral questions

Mechanics and Thermal Physics

Moments and Equilibrium - Couple and torque

- Define a couple as two equal and opposite parallel forces
- Calculate torque as Force × perpendicular distance between forces
- Connect couples to turning steering wheels and opening bottle caps

-Demonstrate couple using a plank fixed at centre
- Apply equal forces in opposite directions
- Calculate torque from experimental data

Why do we need two hands to turn a steering wheel smoothly?

- Uniform plank with central pivot
- Spring balances
- Steering wheel model

- Practical assessment - Written tests - Oral questions

Mechanics and Thermal Physics

Moments and Equilibrium - Applications and resolution of forces

- Describe applications of torque and couples
- Resolve forces to find perpendicular components
- Apply moments to real-life situations like using spanners, screwdrivers and bicycle pedalling

-Discuss applications of moments in daily life
- Solve problems involving forces at angles
- Calculate moments when force is not perpendicular

How do we calculate moments when force is applied at an angle?

- Pictures of applications
- Digital resources
- Problem sheets

- Written tests - Oral questions - Project presentations