UNIT OVERVIEW

This unit connects force and motion to energy. You have already studied momentum and impulse in Term 1, where forces change motion over time. Now you will learn how forces change motion through distance, and how energy changes form but is never destroyed.

By the end of this unit, you will be able to:

• Calculate work done by forces acting at various angles
• Distinguish between positive, negative, and zero work
• Apply the work-energy theorem to solve motion problems
• Identify conservative and non-conservative forces
• Use conservation of mechanical energy to solve problems
• Calculate power and efficiency in real-world situations

Why This Matters

• Vehicles: When a car accelerates, the engine does positive work on it. When brakes slow the car, they do negative work. Electric vehicles use regenerative braking to recover some kinetic energy.
• Power stations: Whether coal-fired or hydroelectric, power stations are rated in megawatts — a direct application of power calculations.
• Mining: Deep mines use hoists to lift ore from underground. Engineers calculate the power required and work done against gravity.
• Sport: Coaches calculate the power athletes generate during sprints to improve performance.

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