ALEVEL物理AUnit复习资料之
alevel物理知识点
alevel物理知识点
A-level物理主要包含以下几个知识点：
1. 经典力学：包括运动学、力学以及能量功率三部分内容。
运动学主要研究物体位置的变化，力学主要研究物体之间的相互作用力，能量功率主要研究能量和做功的问题。
2. 热学：包括热力学和分子物理学。
热力学主要研究热能与机械能、电能等其他形式的能之间的转换，以及转换效率的问题；分子物理学主要研究分子的运动和相互作用，以及与热能相关的现象。
3. 电学：包括静电学和电路学。
静电学主要研究静止电荷之间的相互作用力，以及与电场、电势相关的概念；电路学主要研究电流的形成和流动，以及与电流相关的各种电路元件的作用。
4. 光学：包括几何光学和物理光学。
几何光学主要研究光的直线传播、反射、折射等规律；物理光学主要研究光的波动性质，包括干涉、衍射、偏振等现象。
5. 原子和量子物理：主要研究原子的结构和性质，以及量子力学的基本原理。
包括原子核的结构、放射性衰变、量子力学的波粒二象性等知识点。
以上信息仅供参考，建议查阅A-level物理教材或相关资料获取更全面的信息。
A-LEVEL A2 物理复习资料 particle physics-推荐下载
Section3 particle physics1．The nuclear atom(1)Mass number and atomic number(2)Alpha particle scattering experiment(3)Electrons are accelerated by E and B(4)Write equations using standard nuclear notating(5)Explain why high energies are required to break particles into their constituents and to investigate fine structure(6) de Broglie wavelength λ=h/p(201306R-7)The de Broglie wavelength associated with electrons moving at 2.5 × 106 m s–1 isA .2.9 × 10–4mB .2.4 × 10–8 mC .2.9 × 10–10mD .2.4 × 10–39m (201306-10) The de Broglie wavelength for neutrons used to study crystal structure is 1.2 nm. mass of a neutron = 1.67 × 10–27kgThe speed of these neutrons would beA .3.0 × 106 m s–1 B.3.3 × 102m s–1 C.3.0 × 10–3m s–1 D.3.3 × 10–7m s–1 (201306R-8 )Which of the following is not a valid conclusion from Rutherford’s alpha particle scattering experiment?A .The atom is mainly empty space.B .The mass of the atom is mostly concentrated in the nucleus.C. The nucleus must be positively charged.D .The nucleus must be very small compared to the atom.(201306R-9) Select the row in the table that correctly identifies the composition of a 235U+ ion.92Number of protons Number of neutrons Number of electrons A9214391B9214392C9223591D9323592(201306-1)The nucleus of one of the isotopes of nickel is represented by 6028Ni. Which line correctly identifies a neutral atom of this isotope?Number of protons Number of neutrons Number of electrons A283228B283232C286028D602828（201201-10）The de Broglie wavelength of a moving tennis ball is calculated as 1× 10-33 m. This means that the moving tennis ballA .diffracts through a narrow slit. B.does not behave as a particle.C.does not display wave properties.D.is travelling at the speed of light.(201306R-10) .A transmissionelectron microscope passes abeam of electrons through atiny specimen to form an imageon a viewing screenDue to the wave nature ofelectrons, diffraction occurswhich can blur the image. Toreduce this effect whenviewing a smaller object thebeam must containA .more electrons per second.B .fewer electrons per second.C. faster moving electrons. D .slower moving electrons(201306-13).In an experiment to investigate the structureof the atom, α-particles are fired at a thin metal foil,which causes theα-particles to scatter.(a)(i) State the direction in which thenumber of α-particles detected will be amaximum(ii) State what this suggests about the structure of the atoms in the metal foil.(b) Some α-particles are scattered through180°.State what this suggests about the structure of the atoms in the metal foil.(c)The diagram shows the path of anα-particle passing near to a single nucleus inthe metal foil.(i)Name the force that causesthe deflection of the α-particle.(ii) On the diagram, draw anarrow to show the direction of the force acting on the α-particle at the point where the force is a maximum. Label the force F.(iii) The foil is replaced by a metal of greater proton number.Draw the path of an α-particle that has the same initial starting point and velocity as the one drawn in the diagram.(201301-11) Early in the twentieth century physicists observed the scattering of alpha particles after they had passed through a thin gold foil. This scattering experiment provided evidence for the structure of the atom.(a) State why it is necessary to remove the air from the apparatus that is used for this experiment.(b) From the results of such an experiment give two conclusions that can be deduced about the nucleus of an atom.Conclusion 1Conclusion 2(c) The diagram shows three α-particles ,allwith the same kinetic energy .The path followedby one of the particles is shown . Add to thediagram to show the paths followed by the othertwo particles.(201302-12 )The electron in a hydrogen atom can be described by a stationary wave which is confined within the atom.This means that the de Broglie wavelengthassociated with it must be similar to the size of the atom which is of the order of 10–10 m.(a)(i)Calculate the speed of an electron whose de Broglie wavelength is1.00 × 10–10m. (ii) Calculate the kinetic energy of this electron in electronvolts(b)When βradiation was first discovered ,it was suggested that there were electrons in the atomic nucleus, but it was soon realised that this was impossible because the energy of such an electron would be too great.Suggest why an electron confined within a nucleus would have a much greater energy than the energy calculated in (a)(ii).2．high-energy collisions(1)The role of E in linear particle accelerators(2)r=p/BQ in B(3)⊿E=c2⊿m(4)Units:MeV,GeV,MeV/c2 ,GeV/c2,u(201301-10)The tubes of a linear accelerator (linac) get progressively longer down its length becauseA .the accelerating particles become relativistic.B .the frequency of the applied potential difference changes.C .the accelerating particles must spend the same time in each tube.D .the accelerating particles gain mass（201206-10）As a particle accelerates in a linac, it passes through drift tubes of increasing lengths. This is so thatA.the particle can be given more energy within each tube.B.the frequency of the accelerating voltage can be constant.C.the accelerating voltage can be as high as possible.D.the time spent in the tube by the particle is longer(201306R-6)Charged particles are travelling at a speed v, at right angles to a magnetic field of flux density B. Each particle has a mass m and a charge Q.Which of the following changes would cause a decrease in the radius of the circular path of the particles?A .an increase inB B .an increase in mC .an increase in vD .a decrease in Q (201306-6)A muon has a mass of 106 MeV/c2. The mass of a muon, to two significant figures, isA .1.7 × 10–11 kgB .5.7 × 10–20 kgC .1.9 × 10–28 kg D.1.9 × 10–34 kg (201201-7)The rest mass of a proton is 1.67 × 10–27 kg. This mass, in MeV/c2 is approximatelyA .2.4 × 10–20 B.3.1 × 10–6 C.1.0 D .940(201106-10)The Large Hadron Collider is designed to accelerate protons to very high energies for particle physics experiments. Very high energies are required toA .annihilate hadrons. B.collide hadrons.C .create particles with large mass. D.produce individual quarks(201206-13) An electron and a positron annihilate with the emission of two photons of equal energy. Calculate the wavelength of the photons.(201201-17) (d) The technology suggested in the science fiction series, Star Trek, for powering the Starship Enterprise relied on antimatter. When an anti-hydrogen atom meets a hydrogen atom, they annihilate and produce energy.(i)How much energy, in joules, would be produced by the annihilation ofjust 1 milligram of anti-hydrogen atoms?(ii) Anti-protons are required to produce anti-hydrogen atoms. The total production of anti-protons on Earth over the past 25 years adds up to only a few nanograms.Suggest why so little anti-matter has been created3. Particle accelerators(1) E and B in cyclotron particle accelerators(2) Relativistic effects at speeds near c(201306-9)A cyclotron is a type of particle accelerator. It consists of two metal Dees which are connected to a high frequency voltage supply and are in a strong magnetic field. The particles change their speed becauseA.of the magnetic field they are in.B.the voltage supply is alternating.C.there is a potential difference between the two Dees.D.the magnetic field is at right angles to the Dees.(201306R-11)*11 The diagram shows the basic structure of a cyclotron.With reference to the magnetic field and the alternating potential difference explain how the cyclotron produces a beam of high speed particles.4. Particle theory(1) E and B in particle detectors(2) Charge energy and momentum are conserved in interactions between particles andhence interpret records of particle tracks(3) In the standard quark-lepton model each particle has a corresponding anti-particle meson:quark-anti-quark pairs baryon :quark triplets(4) Write and interpret equations using Standard symbols(201206-9)A pion can decay to produce two leptons. Which one of the following is possible?A.π+→e+ + v e B .π0→e– + v e C.π+→e++ e– D π0→π++ e–(201201-8)A positive kaon (K+) is a meson which includes a strange quark. Its structure could beA . u B. us C. D .usds s d d(201201-9) The K+ is likely to decay tov vA.π+ + μ– + μB. π++π0Cπ++π– D π0 + μ– +μ(201306-7 )The diagram shows the tracks from an event at a point P in a bubble chamber. A magnetic field is directed into the page. The tracks cannot show the production of a proton-antiproton pair with equal kinetic energies becauseA .the curvature is perpendicular to the magnetic field.B .the tracks curve in different directions.C. the tracks have different curvatures.D .there is no track before point P(201306-11)Scientists studying anti-matter recently observed the creation of a nucleus of anti-helium 4, which consists of two anti-protons and two anti-neutrons. The diagram represents the path of a proton through a magnetic field starting at pointX.Add to the diagram the path of an anti-helium 4 nucleus also startingat point X and initially travelling at the same velocity as theproton.Explain any differences between the paths.(201306-14)The photograph shows tracks in aparticle detector.(a) Explain the role of a magnetic field in a particledetector(b) Explain how you can tell that track XY was produced by a particle moving fromX to Y rather than from Y to X.(c)The particle that produced track XY was a π+.Deduce the direction of the magnetic field in the photograph(d) At Y, the π+ decayed into a positively charged muon (μ+) and a muon neutrino. The μ+ has a very short range before decaying into various particles, including a positron which produced the final spiral.(i) Give two reasons why you can deduce that the muon neutrino is neutral.(ii) Explain the evidence from the photograph for the production of the muon neutrino at Y.(201306R-14) .Hadrons are a group of particles composed of quarks. Hadrons can be either baryons or mesons.(a) (i) State the quark structure of a baryon.(ii) State the quark structure of a meson.(b) State one similarity and one difference between a particle and its antiparticle. Similarity:Difference :(c) (i) The table gives some of the properties of up, down and strange quarks.Type of quark Charge/e Strangenessu+2/30d-1/30s-1/3-1One or more of these quarks combine to form aΚ+, a meson with a strangeness of +1.Write down the quark combination of theΚ+..(ii)TheΚ+can decay in the following way Κ+→ µ++ vµK–is the antiparticle of the K+ . Complete the equation below by changing each particle to its corresponding antiparticle in order to show an allowed decay for the K–meson.Κ－→(iii)The rest mass of theΚ+ is 494 MeV/c2Calculate, in joules, how much energy is released if a Κ+ meets and annihilates a K–(201306-12)The table gives some of the properties of the up, down and strange quarks.Type of quark Charge/e Strangenessu+2/30d-1/30s-1/3-1There are nine possible ways of combining u, d and s quarks and their antiquarks to make nine different mesons. These are listed belowu d s d u s s u du u u d d d s s s (a) From the list select the four strange mesons and state the charge and strangeness of each of them.Meson Charge/e Strangeness(b) Some of the mesons in the list have zero charge and zero strangeness.Suggest what might distinguish these mesons from each other.*14 A bubble chamber is a particle detector which makes use of electric and magnetic fields. Explain the role of electric and magnetic fields in a particle detector. (201301-17)In 2011 physicists at the Relativistic Heavy Ion Collider (RHIC) announced the creation of nuclei of anti-helium-4 which consists of anti-protons and anti-neutrons instead of protons and neutrons(a) ‘Ordinary’ helium-4 is written as 42He.What do the numbers 4 and 2 represent?(b) In the RHIC experiment, nuclei of gold 19779Au travelling at speeds greater than2.99 × 108m s–1, in opposite directions, collided, releasing energies of up to 200 GeV. After billions of collisions, 18 anti-helium nuclei had been detected.(i) What is meant by ‘relativistic’ in the collider’s name?(ii) State why it is necessary to use very high energies in experiments such as these. (iii) Show that the mass of a stationary anti-helium nucleus is about 4 GeV/c2(iv) State why the small number of anti-helium nuclei produced only survive for a fraction of a second.(v) A slow moving anti-helium nucleus meets a slow moving helium nucleus. If they were to combine to produce 2 high energy gamma rays, calculate the frequency of each gamma ray.(c) There are two families of hadrons, called baryons and mesons. Baryons such asprotons are made of three quarks.(i) Describe the structure of a meson(ii) Up quarks have a charge of +2/3e and down quarks a charge of –1/3e.Describe the quark composition of anti-protons and anti-neutrons and use this to deduce the charge on each of these particles.（201206-18）18 (a) Physicists were able to confidently predict the existence of a sixth quark. State why(b) The mass of the top quark was determined by an experiment. Collisions between protons and anti-protons occasionally produce two top quarks.(i) How do the properties of a proton and an anti-proton compare?(ii) After the collision the two top quarks move in opposite directions with the same speed. Explain why.(c) The two top quarks decay rapidly into two muons and four jets of particles. These can be detected and their momenta measuredThe diagram shows an end-on view of the directions of the four jets (J1 to J4) of particles. The two muons are shown as μ1and μ2. A muon neutrino is also produced but cannot be detected, so is not shown. Each momentum is measured inGeV/c.(i)Explain why GeV/c is a valid unit for momentum.(ii) The vector diagram shown below is not complete. Add to the diagram arrows to represent the momenta of J3 and J4.(iii) Complete the diagram to determine the magnitude of the momentum of the muon neutrino.(iv) Show that the total energy of all the products of this event is about 300 GeV. (v) Deduce the mass of a top quark in GeV/c2.(vi) Suggest why it took a long time to find experimental evidence for the top quark.。
A-LEVEL物理A2Unit5复习资料5
Section 5 nuclear decay：Revision spread ：1.nuclear radiationCheckpoints :（1) show an awareness of the existence and origin of background radiation ，past and present.（2） investigate and recognize nuclear radiations (αβγ）from theirpenetrating power and ionizing ability 。
（3） describe the spontaneous and random nature of nuclear decay.（4) determine the half-lives of radioactive isotopes graphically。
(5） recognize and use the expressions for radioactive decay dN/dt=—λN,λ=ln2/t1/2 N=Ne—λt(6）discuss the applications of radioactive materials，including ethical and environmental issues。
（201306r—2）In a famous thought experiment, Schrödinger imagined that a cat is locked in a box, along with a radioactive atom that is connected to a tube containing a deadly poison。
If the atom decays, it causes the tube to smash and the cat to die. The random nature of radioactive decay means that the radioactive atom willA 。
alevel物理aqa第一章知识点汇总
alevel物理aqa第一章知识点汇总In AQA A-Level Physics, the first chapter covers several key concepts, including mechanics, motion, forces, energy, and materials. 这一章是物理课程的基础，对于学生来说非常重要。
其中，力、运动、材料和能量等相关概念是学生需要深入理解和掌握的重要内容。
Understanding these concepts lays the foundation for later chapters and topics in physics. 理解这些基本概念对于学生在后续学习物理课程时起到了很重要的作用。
One of the key areas covered in this chapter is mechanics, which focuses on the study of motion and the forces that cause motion. 这一章重点讲述了力学，它专注于研究物体的运动以及导致这种运动的力。
Students will learn about Newton's laws of motion, the concept of momentum, and circular motion. 学生们需要理解牛顿运动定律、动量的概念以及圆周运动等内容。
These concepts provide a framework for understanding how objects move and interact with one another. 这些概念为学生们提供了分析物体运动和相互作用的框架。
Another important topic in the first chapter is energy, including different forms of energy and the conservation of energy. 另一个重要的主题是能量，包括不同形式的能量以及能量守恒定律。
alevel物理知识点总结
alevel物理知识点总结IntroductionA-level Physics is a comprehensive course that covers a wide range of topics in physics, from classical mechanics and thermodynamics to quantum physics and astrophysics. It is a challenging subject that requires a sound understanding of mathematical concepts and scientific principles. In this summary, we will cover some of the key knowledge points in A-level Physics, including important theories, laws, and equations.Classical MechanicsClassical mechanics is the branch of physics that deals with the motion of objects and the forces that act on them. It is based on the principles of Newtonian mechanics, which were developed by Sir Isaac Newton in the 17th century. The key concepts in classical mechanics include:- Newton's Laws of Motion: Newton's three laws of motion are fundamental principles that describe the behavior of objects in motion. The first law states that an object at rest will remain at rest, and an object in motion will remain in motion at a constant velocity, unless acted on by an external force. The second law relates the force acting on an object to its mass and acceleration, and the third law states that for every action, there is an equal and opposite reaction.- Conservation of Energy: The principle of conservation of energy states that the total energy in a closed system remains constant over time. This includes both kinetic energy (energy of motion) and potential energy (energy due to an object's position).- Conservation of Momentum: The principle of conservation of momentum states that the total momentum of an isolated system remains constant, provided no external forces act on the system.ThermodynamicsThermodynamics is the branch of physics that deals with the relationships between heat, work, and energy. It is a fundamental concept in the study of physical systems and their behavior. The key concepts in thermodynamics include:- The First Law of Thermodynamics: The first law of thermodynamics, also known as the principle of conservation of energy, states that the total energy of an isolated system remains constant. This means that energy cannot be created or destroyed, only transferred from one form to another.- The Second Law of Thermodynamics: The second law of thermodynamics states that the total entropy of an isolated system will always increase over time. This implies that processes occurring in nature are irreversible, and that there is a directionality to the flow of energy.- The Carnot Cycle: The Carnot cycle is a theoretical thermodynamic cycle that represents the most efficient possible heat engine, and serves as a benchmark for the maximum efficiency of real-world heat engines.ElectromagnetismElectromagnetism is the branch of physics that deals with the relationship between electricity and magnetism, and the behavior of charged particles. It is a fundamental concept in the study of electromagnetics. The key concepts in electromagnetism include:- Coulomb's Law: Coulomb's law describes the force between two point charges, and is given by the equation F = k * (q1 * q2) / r^2, where F is the force, k is the electrostatic constant, q1 and q2 are the magnitudes of the charges, and r is the distance between the charges.- Ampere's Law: Ampere's law describes the relationship between an electric current and the magnetic field it generates. It is given by the equation ∮B * dl = μ0 * I, where B is the magnetic field, dl is an infinitesimal element of length, μ0 is the permeability of free space, and I is the electric current.Quantum PhysicsQuantum physics is the branch of physics that deals with the behavior of particles at the atomic and subatomic level. It is a highly complex and abstract field of study, and has led to many groundbreaking discoveries in physics. The key concepts in quantum physics include:- Schrödinger's Wave Equation: Schrödinger's wave equation describes the behavior of quantum particles by treating them as waves of probability. It is used to calculate the probability distribution of a particle's position and momentum.- The Heisenberg Uncertainty Principle: The Heisenberg uncertainty principle states that it is impossible to know both the position and momentum of a particle with absolute certainty. There is an inherent uncertainty in the measurement of these quantities, which is given by the equation Δx * Δp ≥ h/4π, where Δx is the uncertainty in position, Δp is the uncertainty in momentum, and h is Planck's constant.AstrophysicsAstrophysics is the branch of physics that deals with the study of celestial objects and the universe as a whole. It involves the application of physical principles to understand the behavior of stars, galaxies, and other astronomical phenomena. The key concepts in astrophysics include:- The Big Bang Theory: The Big Bang theory is the prevailing cosmological model for the origin of the universe. It states that the universe began as a singularity and has been expanding ever since, leading to the formation of galaxies, stars, and planets.- The Hubble Law: The Hubble law describes the relationship between the distance to a galaxy and its recessional velocity, and is given by the equation v = H0 * d, where v is the recessional velocity, d is the distance, and H0 is the Hubble constant.ConclusionA-level Physics covers a wide range of topics and concepts, from classical mechanics and thermodynamics to quantum physics and astrophysics. It is a challenging subject that requires a deep understanding of mathematical principles and scientific theories. This summary has covered some of the key knowledge points in A-level Physics, and serves as a useful reference for students and enthusiasts of physics.。
alevel物理a2知识点
alevel物理a2知识点
A2阶段物理知识点包括以下内容：
1. 圆周运动：研究物体绕固定点旋转的基本规律，如角速度、周期等。
2. 万有引力场：描述物体在地球或其他天体附近受到的引力作用，以及物体之间的万有引力关系。
3. 理想气体：研究理想气体状态方程和理想气体定律，包括压强、温度、体积等之间的关系。
4. 温度：研究温度的概念、温标的建立以及温度与热量、内能之间的关系。
5. 物质的热运动：描述分子的无规则运动和热传导的基本概念，如分子动理论、热容等。
6. 振动：研究简谐振动的规律，包括振幅、频率、相位等。
7. 通讯：介绍电磁波的传播和通讯方式，如无线电波、光波等。
8. 电容：研究电容的概念和电容器的充放电过程，包括电容器、电容等。
9. 电子元件：介绍基本的电子元件，如电阻、电容、电感等及其特性。
10. 磁场：研究磁场的基本概念和磁力作用，如磁场强度、磁通量等。
11. 电磁感应：描述电磁感应现象和法拉第电磁感应定律，包括感生电动势等。
12. 交流电：研究交流电的产生、传输和利用，如交流电的波形、频率等。
13. 量子物理：介绍量子力学的基本概念和原理，如波粒二象性、量子态等。
此外，A2阶段物理知识点还包括AS阶段的所有内容，如物理量和单位、测量技术、运动学、动力学、力密度压强、功能量功率、固体形变、波、波的叠加、电场、电流、直流电路等。
同时，A2阶段还有实验技能考察，注重综合的科学实验素养考察，如设计实验，分析和统计检验等能力。
以上知识点只是简要列举，具体内容可能因教材或考试大纲而有所不同。
建议查阅相关教材或考试大纲以获取更详细的信息。
ALevel物理知识点梳理系列一
A L e v e l物理知识点梳理系列一IMB standardization office【IMB 5AB- IMBK 08- IMB 2C】A-L e v e l物理知识点梳理系列（一）物理量及单位(physicalquantitiesandunits)A-level物理AS阶段涵盖了物理量、测量、运动学、力学、功与能量、物质与材料学、波、电学以及核物理等九大版块。
本次知识梳理将对各个板块所涵盖的知识点、重要公式以及相关的典型真题进行精讲精练。
希望通过本次的系统复习，同学们能够对各章节内容掌握得更加清晰透彻，形成知识体系，在解题过程中能够及时将题目与其背后所考察的知识点对应起来。
本期将对物理量(physicalquantitiesandunits)进行专题讲解，这一部分是AS物理的开篇内容，与其他章节比相对简单，但又是学好后续章节的基础。
CIE物理paper1的前两小题及paper2的第一题一般会考察此章节内容。
一、矢量与标量Vectorsandscalarsscalar:physicalquantitythathasmagnitudeonly.vector:physicalquantitythathasmagnitudeanddirection.区分矢量与标量的唯一标准为所描述的物理量是否包含方向(direction)这一要素.包含方向要素则为矢量(vector)，如位移(displacement)、速度(velocity)等；若仅用大小(ma gnitude)即可描述，则该物理量为标量，如温度(temperature),功率(power)等。
真题解析S041WhichpaircontainsonevectorandonescalarquantityAdisplacement:accelerationBforce:kineticenergyCmomentum:velocityDpower:speed此题为04年春季paper1的第一小题。
alevel物理知识点盘点
alevel物理知识点盘点英文回答：Physics is a fascinating subject that explores the fundamental principles of the universe. As an A-level student, there are several key topics that you will cover in your physics course. Let's take a look at some of the important knowledge points in A-level physics.1. Mechanics: Mechanics is the study of motion and forces. You will learn about concepts such as Newton's laws of motion, momentum, energy, and circular motion. For example, you will understand how an object's velocity changes when a force is applied to it, or how the conservation of momentum works in collisions.2. Waves: Waves are a common phenomenon in nature, and in physics, you will study the properties and behavior of waves. This includes topics like wave motion, wave interference, and the different types of waves such assound waves and electromagnetic waves. For instance, youwill learn how waves can be reflected, refracted, or diffracted, and how they can be used in variousapplications like communication systems.3. Electricity and Magnetism: This topic deals with the principles of electricity and magnetism. You will learn about electric circuits, Ohm's law, electromagnetic induction, and the behavior of magnetic fields. For example, you will understand how electric current flows in a circuit and how magnetic fields can be used to generate electricity.4. Quantum Physics: Quantum physics is a branch of physics that deals with the behavior of particles at the atomic and subatomic level. You will learn about concepts such as wave-particle duality, quantum mechanics, and the uncertainty principle. For instance, you will explore how electrons can exist in multiple energy statessimultaneously and how the behavior of particles can be described by probability.5. Thermodynamics: Thermodynamics is the study of heatand energy transfer. You will learn about topics like the laws of thermodynamics, heat engines, and entropy. For example, you will understand how energy is transferred between systems and how heat engines can convert heat into useful work.中文回答：物理是一门令人着迷的学科，探索着宇宙的基本原理。
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Section 6: OscillationsRevision spread1 : Simple harmonic motionCheckpoints : (1)recall that the condition for simple harmonic motion is F=-kxIdentify situations in which simple harmonic motion will occur.(2) recognize and use the expressions a=-ω2x, a=-Aω2xcosωt,v=-Aωsinωt,x=A cosωt,and T=1/f=2π/ωas applied to asimple harmonic oscillator.(3) obtain a displacement-time graph for an oscillating objectand recognize that the gradient at a point gives the velocity atthat point.（201306-1）A mass is bouncing on the end of a vertical spring. Its motion will be simple harmonic if the springA .can store energy.B .has elasticity.C .is hung vertically.D .obeys Hooke’s law.（201206-4）Which of the following is not an example of simple harmonic motion?A A car bouncing on its suspension system.B A child jumping on a trampoline.C A person bouncing on the end of a bungee cord.D A swinging pendulum in a grandfather clock.201301（201201-13）(a) Define simple harmonic motion(b) The graph shows the variation in water level displacement with time for the water in a harbour. The water level displacement varies with simple harmonic motion.(i) Use the graph to calculate the amplitude and the time period of the variation in the water level displacement.(ii) Show that the maximum rate of change of water level displacement is about 0.6 m hour–1.(iii) On the axis below sketch how the rate of change of water level displacement varies with time for the interval 0–30 hours. The variation in water level displacement with time has been drawn for you. You need not add any numerical values to the y-axis.Revision spread2 :Energy and damping in SHMCheckpoints : (1)Recall that the total energy of an undamped SHM system remains constant and recognize ad use expressions for the totalenergy of an oscillator.(2) Distinguish between free and damped oscillations(201306r-7) An object is hung from a vertical spring and undergoes undamped simple harmonic motion. It is correct to say that there are no changes in theA .elastic potential energy of the oscillating system.B .gravitational potential energy of the oscillating system.C .kinetic energy of the oscillating system.D .total energy of the oscillating system.(201306-9)For an object undergoing simple harmonic motion select the graph that represents the variation of kinetic energy with displacement.(201306-10) For an object undergoing simple harmonic motion select the graph that represents the variation of the total energy with displacement.Revision spread3 :Forced oscillations and resonance .Checkpoints : (1)Distinguish between free, damped and forced oscillations .(2) Investigate and recall how the amplitude of a forced oscillationchanges at and around the natural frequency of a system .Describe qualitatively how damping affects resonance .(3)Explain how damping and the plastic deformation of ductilematerials reduce the amplitude of oscillation .(201306-8) A car is travelling over a rough road surface. At low speed the ride is very bumpy with the car and its occupants suffering large amplitude vertical oscillations. However, when the car is driven at a higher speed the ride gets smoother. This is because at the higher speedA .the car leaves the ground and misses the bumps.B .the car crushes the bumps and makes the road smoother.C .there is a greater amount of damping in the car’s suspension.D .the car’s suspension oscillates at a greater frequency than its natural frequency (201206-7) When one system is driven into oscillation by another, the driven system A. exhibits resonance. B. has a large increase in amplitude.C. vibrates at its natural frequency.D. vibrates at the driver frequency. (201301-4)New buildings in earthquake zones are often designed to be earthquake resistant .Such buildings incorporate mechanisms to reduce the transfer of kinetic energy from the ground to the building. Which of the following would be the most important property of a material used in such a mechanism ?A.densityB. ductilityC. stiffnessD.strength(201306-13) The diagram shows a number of pendulums hanging from a single thread. Pendulum X has a heavy lead sphere as the bob and the others have low mass bobs. When X is set into motion energy is transferred to the others which all begin to oscillate.After a short time C is observed tohave the largest amplitude ofoscillation.(a) Explain why pendulum C has the largest amplitude of oscillation.(b)For an efficient energy transfer pendulum C must be at rest when pendulum X has its maximum kinetic energy. The graph below shows how the displacement of pendulum X varies with time.Mark a point P on this graph showing an instant when pendulum X has a maximum kinetic energy, and add a curve to show how the displacement of pendulum C varies over the same time interval.(201306r-18)A baby-bouncer is a light harness, into which a baby can be placed, suspended by a vertical spring.The height of the baby-bouncer is adjusted so that the baby’s feet are a few centimetres above the floor when the baby is in equilibrium in the harness. If the baby is then displaced downwards and released, the system oscillates vertically with simple harmonic motion. It is stated in a textbook that “a mass-spring system that obeys Hooke’s law will lead to simple harmonic motion when the mass is displaced.”*(a) Exp lain why a system consisting of a mass and a spring that obeys Hooke’s law may be set into simple harmonic motion.(b) The acceleration experienced by a baby of mass 8.2 kg is 0.49 m s-2when the displacement from the equilibrium position is 3.0 cm.Show that the period of vertical oscillations for this baby is about 1.6 s.(c) The amplitude of the oscillations quickly decreases, so the baby has to keep kicking on the floor to maintain them.(i) State the name given to oscillations that die away quickly.(ii) State the name that is given to oscillations such as those that are kept going by the baby kicking on the floor.(iii) If the baby kicks on the floor at a certain frequency, the amplitude of the bounces can be made to increase to a maximum.Name this effect and calculate the frequency at which it occurs(d) The baby is replaced by a baby of less mass. This baby also kicks to produce maximum amplitude of oscillation. Without further calculation, explain how the frequency at which the baby must kick compares to that for the larger mass baby. (201206-17) The photograph shows a nodding tiger toy. The tiger is placed on a car’s dashboard and its head nods up and down as the car is driven along a rough road surface. It is n oticed that at a particular speed the tiger’s head vibrates with maximum amplitude.(a) (i) What is the name of this phenomenon?(ii) Describe the conditions necessary for thisphenomenon to occur.(b) (i) The graph shows the variation of accelera tion with time for the tiger’s head. Using values from the graph calculate the amplitude of oscillation of the tiger’s head.(ii) Sketch a graph of the head’s displacement against time over the same time interval on the axes below.(201201-14)*When a tuning fork is struck with a rubber hammer, a pure sound of fixed frequency is produced. The photograph shows a tuning fork connected to a wooden sounding box..The sounding box amplifies the sound produced when the tuning fork is struck ..The sound lasts for a shorter time than if the tuning fork were t be struck identically but without the sounding box.Explain these observations.。