P3 REVISION – CHAPTER 1 – MEDICAL APPLICATIONS OF PHYSICS X-rays: Explain what an x-ray is: Describe some of the safety issues with X-rays: Describe what a CT scanner is: Ultrasound: Describe how an ultrasound works: Explain how an ultrasound can be used to measure distance: Explain some of the therapeutic uses of ultra sound: Lenses: Describe how a convergent lens works: Describe how a divergent lens works: Describe how the lens works in the eye: Endoscope: Describe how an endoscope works: Describe how we use endoscopes in medicine: Refraction index: The refractive index of the substance, 𝑛= sin 𝑖 sin 𝑟 Where 𝑖 is the angle of incidence and 𝑟 is the angle of refraction. KEY WORDS: Radiograph Refraction index Charge-couple device Endoscope Converging lens CT scanner Diverging lens Transducer Principal focus A-scan Magnifying Refraction Focal length Snell’s law Image ASSESSMENT:

P3 REVISION – CHAPTER 2 – USING PHYSICS TO MAKE THINGS WORK Moments: Describe what a moment it: Complete the equation: Moment = ____ X perpendicular distance from the line of the force to the pivot ______ newtons ________ ______ Nm m Moments in balance: When a see-saw is balanced: the anticlockwise moment due to W1 about the pivot = W1d1 the clockwise moment due to W2 about the pivot = W2d2 Calculate W1, if W2 = 7.0N, d1 = 0.40m and d2 = 0.25m Circular motion: Explain centripetal force and the factors that affect it: Centre of mass: Describe what the centre of mass of an object is: Draw the centre of mass on these shapes: Stability: Explain the following: Tractor safety: Bus tests: High chairs: The pendulum: Describe the motion of a pendulum: The frequency of the oscillations is the number of complete cycles of oscillation per second. the time period = 1 𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦 𝑜𝑓 𝑡ℎ𝑒 𝑜𝑠𝑐𝑖𝑙𝑙𝑎𝑡𝑖𝑜𝑛𝑠 (𝑖𝑛 ℎ𝑒𝑟𝑡𝑧, 𝐻𝑧) (in seconds, s) Hydraulics: Describe how machines use hydraulics: The formula for pressure is: Pressure (Pa or N/m2) = 𝑓𝑜𝑟𝑐𝑒 (𝑁) 𝑎𝑟𝑒𝑎 ( 𝑚 2 ) KEY WORDS: Load Pressure Effort Pascal (Pa) Pivot Hydraulic Centripetal Line of action Centre of mass Oscillation Equilibrium Amplitude Moments Frequncy Resultant ASSESSMENT:

P3 REVISION – CHAPTER 3 – USING MAGNETIC FIELDS TO KEEP THINGS MOVING Explain how an electromagnet works: Explain Fleming’s left hand rule: Explain how an electric motor works: Explain electromagnetic induction: Explain how a transformer works: The transformer equation is: 𝑝𝑑 𝑎𝑐𝑟𝑜𝑠𝑠 𝑝𝑟𝑖𝑚𝑎𝑟𝑦, 𝑉 𝑃 𝑝𝑑 𝑎𝑟𝑜𝑠𝑠 𝑠𝑒𝑐𝑜𝑛𝑑𝑎𝑟𝑦, 𝑉 𝑆 = 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑡𝑢𝑟𝑛𝑠 𝑜𝑛 𝑝𝑟𝑖𝑚𝑎𝑟𝑦, 𝑛 𝑝 𝑛𝑢𝑚𝑏𝑒𝑟𝑠 𝑜𝑓 𝑡𝑢𝑟𝑛𝑠 𝑜𝑛 𝑠𝑒𝑐𝑜𝑛𝑑𝑎𝑟𝑦, 𝑛 𝑠 If the transformer is 100% efficient: 𝑝𝑜𝑤𝑒𝑟 𝑠𝑢𝑝𝑝𝑙𝑖𝑒𝑑 𝑡𝑜 𝑡ℎ𝑒 𝑡𝑟𝑎𝑛𝑠𝑓𝑜𝑟𝑚𝑒𝑟=𝑝𝑜𝑤𝑒𝑟 𝑑𝑒𝑙𝑖𝑣𝑒𝑟𝑒𝑑 𝑏𝑦 𝑡ℎ𝑒 𝑡𝑟𝑎𝑛𝑠𝑓𝑜𝑟𝑚𝑒𝑟 𝑝𝑟𝑖𝑚𝑎𝑟𝑦 𝑝𝑑 ×𝑝𝑟𝑖𝑚𝑎𝑟𝑦 𝑐𝑢𝑟𝑟𝑒𝑛𝑡=𝑠𝑒𝑐𝑜𝑛𝑑𝑎𝑟𝑦 𝑝𝑑 ×𝑠𝑒𝑐𝑜𝑛𝑑𝑎𝑟𝑦 𝑐𝑢𝑟𝑟𝑒𝑛𝑡 𝑉 𝑃 × 𝐼 𝑃 = 𝑉 𝑆 × 𝐼 𝑆 KEY WORDS: South pole Induction North pole Transformer Magnetic pole National grid Magnetic field lines Step-up transformer Motor effect Step-down transformer ‘Split-ring’ commutator ASSESSMENT: