Global challenges — OCR GCSE Physics
In summary: Global challenges is a key topic in OCR GCSE Physics. Key exam tip: Ensure you can clearly define and distinguish between thinking distance, braking distance, and total stopping distance.
Exam Tips for Global challenges
- Ensure you can clearly define and distinguish between thinking distance, braking distance, and total stopping distance.
- Be prepared to perform calculations involving ratios and proportional reasoning.
- Practice estimating magnitudes for speed, acceleration, and force in everyday transport contexts.
- Understand the physics behind safety features like crumple zones in terms of force and deceleration.
- Ensure you can explain why high voltage is used in the National Grid to reduce energy loss
- Be prepared to perform calculations involving transformer ratios and power transfer
- Clearly distinguish between the functions of the three mains wires (live, neutral, earth)
- Ensure you can distinguish between the roles of P and S waves in seismic exploration
Common Mistakes
- Confusing the factors that affect thinking distance with those that affect braking distance
- Failing to distinguish between thinking distance and braking distance
- Incorrectly assuming that alcohol, drugs, or tiredness affect braking distance rather than thinking distance
- Errors in unit conversion between non-SI and SI units
- Confusing energy with power (e.g., solar power)
- Incorrectly believing higher voltages are applied along power lines rather than across them
Marking Points
- Recall of typical speeds for various transport systems
- Estimation of everyday accelerations
- Calculation of reaction times and stopping distances
- Distinction between thinking distance and braking distance
- Explanation of factors affecting thinking and braking distances
- Analysis of dangers associated with large decelerations
- Application of ratios and proportional reasoning for unit conversions
- Distinction between renewable and non-renewable energy sources
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