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Global challenges
Revision and exam practice for Global challenges.
28
Objectives
10
Flashcards
10
Questions
90 min
Study time
OcrGcsePhysics A GatewayGlobal challenges
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28 objective pages available
Understanding Typical Speeds in Everyday Life1 objectives
- Retrieve and apply knowledge of typical speeds encountered in everyday experience for wind and sound, and for walking, running, cycling and other transportation systems.
Estimating Everyday Accelerations1 objectives
- Obtain a justified estimate of the magnitudes of everyday accelerations.
Understanding Ratios, Proportional Reasoning, and Rates in Physics1 objectives
- Develop knowledge and skill in calculations using ratios and proportional reasoning to convert units and to compute rates.
Measuring Human Reaction Time and Typical Results1 objectives
- Account for methods of measuring human reaction times and recall typical results.
Understanding Braking Distance and Road Safety1 objectives
- Account for the factors which affect the distance required for road transport vehicles to come to rest in emergencies and the implications for safety.
Understanding Stopping Distances for Road Vehicles1 objectives
- Obtain a justified estimate of the way the distances required for road vehicles to stop in an emergency, varies over a range of typical speeds.
Dangers of Large Decelerations1 objectives
- Account for the dangers caused by large decelerations.
Estimating Forces in Road Situations (Higher Tier)1 objectives
- Obtain a justified estimate of the forces involved in typical situations on a public road.
Estimating Road Transport Physics1 objectives
- Develop secure knowledge and application of estimate, for everyday road transport, the speed, accelerations and forces involved in large accelerations
Understanding Energy Sources: Renewable vs. Non-renewable1 objectives
- Communicate the key features of the main energy sources available for use on Earth, compare the ways in which they are used and distinguish between renewable and non-renewable sources.
Patterns and Trends in Energy Resource Use1 objectives
- Account for patterns and trends in the use of energy resources.
Electrical Power Transmission in the National Grid1 objectives
- Retrieve and apply knowledge of that, in the national grid, electrical power is transferred at high voltages from power stations, and then transferred at lower voltages in each locality for domestic use.
Transformers in Power Transmission1 objectives
- Retrieve and apply knowledge of step-up and step-down transformers are used to change the potential difference as power is transferred from power stations.
Efficiency of the National Grid1 objectives
- Account for the way the national grid is an efficient way to transfer energy.
Higher: Power Transmission and Transformers1 objectives
- Develop knowledge and skill in the potential differences and numbers of turns of a transformer to the power transfer involved; relate this to the advantages of power transmission at high voltages.
Understanding Domestic Electricity Supply in the UK1 objectives
- Retrieve and apply knowledge of the domestic supply in the UK is a.c. at 50 Hz and about 230 volts.
Direct Current (DC) vs. Alternating Current (AC) Voltage1 objectives
- Account for the difference between direct and alternating voltage.
Understanding Mains Electricity Wires: Live, Neutral, and Earth1 objectives
- Retrieve and apply knowledge of the differences in function between the live, neutral and earth mains wires, and the potential differences between these wires.
Dangers of the Live Wire in Mains Circuits1 objectives
- Account for a live wire may be dangerous even when a switch in a mains circuit is open, and explain the dangers of providing any connection between the live wire and earth.
Red-shift and the Expanding Universe1 objectives
- Account for the red-shift of light galaxies which are receding only). The change with distance galaxy’s speed is evidence expanding universe.
Red Shift as Evidence for the Big Bang1 objectives
- Account for the way red shift and other can be linked to the Big-Bang.
The Birth and Stability of Our Sun1 objectives
- Retrieve and apply knowledge of our Sun was formed from dust and gas drawn together by gravity and explain how this caused fusion reactions, leading to equilibrium between gravitational collapse and expansion due to the energy released during fusion.
Understanding Thermal Radiation Emission1 objectives
- Account for all bodies emit radiation, and that the intensity and wavelength distribution of any emission depends on their temperatures.
Understanding Our Solar System1 objectives
- Retrieve and apply knowledge of the main features of our solar system, including the similarities and distinctions between the planets, their moons, and artificial satellites.
Gravity's Role in Changing Planetary Velocity but Constant Speed in Circular Orbits (Higher)1 objectives
- Account for for circular orbits, how the force of gravity can lead to changing velocity of a planet but unchanged speed (qualitative only).
Higher: Stable Orbits and Their Dependence on Speed and Radius1 objectives
- Account for how, for a stable orbit, the radius must change if this speed changes (qualitative only).
Temperature Equilibrium and Radiation Balance (Higher)1 objectives
- Account for the way the temperature of a body is related to the balance between incoming radiation absorbed and radiation emitted; illustrate this balance using everyday examples and the example of the factors which determine the temperature of the Earth.
Wave Behaviour in Solids and Liquids for Exploration (Higher)1 objectives
- Develop secure knowledge and application of explain, in qualitative terms, how the differences in velocity, absorption and reflection between different types of waves in solids and liquids can be used both for detection and for exploration of structures which are hidden from direct observation, notably in the Earth’s core and in deep water
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Practice preview
- What is the function of a step-up transformer within the National Grid?
- A HGV (Heavy Goods Vehicle) has a mass of approximately 30,000 kg. If it accelerates from rest to 10 m/s in 20 seconds, estimate the acceleration and the average propelling force acting on the HGV. Show your working. [4 marks]
- A power station generates 50 MW (megawatts) of electrical power. This power is transmitted through cables with a total resistance of 0.5 Ω. (a) Calculate the power lost as heat if the electricity is transmitted at a current of 10,000 A. (b) Explain why transmitting electricity at a much higher voltage is more efficient, even if the total power generated remains the same. Use a calculation based on the same power (50 MW) but transmitted at 400,000 V to support your explanation, given the same cable resistance. [6 marks]
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