Motion, forces and energy

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Sample objectives

What this unit covers

• Physical quantities and measurement techniques: Explain how to use rulers and measuring cylinders to measure length or volume accurately.
• Physical quantities and measurement techniques: Explain the methods for measuring different time intervals using both analog clocks and digital timers.
• Motion: Explain speed as the distance covered in a specific time period and use the formula v = s/t.
• Motion: Explain velocity as speed with a specified direction.
• Mass and weight: Recognize that mass indicates the amount of matter in an object when it is stationary relative to the observer.
• Mass and weight: Acknowledge that weight is the force exerted by gravity on an object that possesses mass.
• Density: Define density as the mass of an object divided by its volume; remember and apply the formula m = ρ V.
• Density: Explain the process for measuring the density of a liquid, a solid with a regular shape, and a solid with an irregular shape that sinks in a liquid (using volume displacement), including necessary calculations.
• Effects of forces: Understand that forces can cause changes in an object's size and shape.
• Effects of forces: Create, analyze, and interpret load-extension graphs for elastic materials, including the relevant experimental methods.
• Turning effect of forces: Explain the concept of the moment of a force as an indicator of its ability to cause rotation, and provide common examples from daily life.
• Turning effect of forces: Define the moment of a force using the formula moment = force × perpendicular distance from the pivot, and be able to recall and apply this formula.
• Centre of gravity: Explain the concept of the centre of gravity.
• Centre of gravity: Outline a method to find the centre of gravity of a non-uniform flat shape through experimentation.
• Momentum: Understand momentum as the product of mass and velocity; remember and apply the formula p = mv.
• Momentum: Understand impulse as the product of force and the duration for which the force acts; remember and apply the formula ∆ impulse = F t = ( mv ).
• Energy: Identify the various forms in which energy can be stored, including kinetic, gravitational potential, chemical, elastic (strain), nuclear, electrostatic, and internal (thermal) energy.
• Energy: Explain how energy is moved between different stores during various events and processes, providing examples such as mechanical work, electrical work, heating, and energy transfer through waves.
• Work: Recognize that the work performed, whether mechanical or electrical, corresponds to the energy that has been transferred.
• Work: Memorize and apply the formula for mechanical work, which is expressed as ∆ W = Fd = E.
• Energy resources: Explain how useful energy can be derived or electrical power can be produced from various sources, including: (a) chemical energy in fossil fuels (b) chemical energy in biofuels (c) water energy from waves, tides, and hydroelectric dams (d) geothermal energy (e) nuclear energy (f) solar energy for electricity generation (solar cells) (g) solar energy for heating water (solar panels) and wind energy, mentioning the roles of a boiler, turbine, and generator where applicable.
• Energy resources: Discuss the pros and cons of each energy generation method regarding their renewability, availability, reliability, scale, and environmental effects.
• Power: Explain power as the amount of work completed in a specific time frame and as the energy transferred in a specific time frame; remember and apply the formulas W = P × t and P = ∆E / t.
• Pressure: Explain pressure as the force applied over a specific area and remember to apply the formula F = p × A.
• Pressure: Discuss how pressure changes based on the amount of force and the size of the area, using common real-life situations as examples.