1. Construct a distance time graph for a moving body in a straight line when the body is stationary or moving with constant speed.

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1 Additional Physics Questions: 1. Construct a distance time graph for a moving body in a straight line when the body is stationary or moving with constant speed. 2. Construct a velocity timer graph for a body moving with a constant velocity 3. What is the difference between speed and velocity? Speed is the rate of motion, or the rate of change of position. Speed is measured in the same physical units of measurement as velocity, but does not contain an element of direction. Speed is the magnitude component of velocity. Velocity contains both the magnitude and direction components. 4. How do you calculate speed? Speed = Distance / Time 5. How do you calculate speed from a distance time graph? The gradient of a distance time graph tells us the speed at which the object is moving. We calculate the gradient of a line 6. What is acceleration? The acceleration of an object is its change in velocity per second. Acceleration; change in Velocity (m/s) / time taken for that change (s) (M/s) 2 7. How do you calculate acceleration from a velocity time graph? The slope of the line on a velocity time graph represents acceleration. 8. What does the area under a velocity time graph represent? The area under the velocity time graph represents distance travelled. 9. What is terminal velocity? If an object falls freely it will accelerate downwards because of the force of the weight due to gravity, eventually its acceleration will decrease because of air resistance, the object will reach a constant velocity when the drag force ( air resistance) on it is equal and opposite to its weight. We call this velocity its terminal velocity. 10. How do you calculate weight? Weight (n) = Mass (kg) x Earth gravitational pull (n/kg) 11. What is the unit of measurement for weight? Newton. 12. What is a resultant force? An object may have several different forces acting on it, which can have different strengths and directions. But they can be added together to give the resultant force. This is a single force that has the same effect on the object as all the individual forces acting together.

2 When all the forces are balanced, the resultant force is zero. A stationary object remains stationary. A moving object keeps on moving at the same speed in the same direction. When all the forces are not balanced, the resultant force is not zero. A stationary object begins to move in the direction of the resultant force. A moving object speeds up, slows down or changes direction depending on the direction of the resultant force. 13. Show how mass, force and acceleration are related by an equation. F = ma Force = Mass x Acceleration. 14. What is friction? Friction is a resistant force; it is a force in the opposite direction of the movement of the object. Air resistance is a frictional force. 15. What affects braking distance? The braking distance of a car is the distance between the brakes being applied and the car coming to a halt. The factors that affect the braking distance; The mass of the car, the greater the car, the greater the braking distance. The speed of the car, the faster the car, the greater the braking distance. The force from the brakes, the greater the force from the brakes, the shorter the braking distance. The road conditions, on a wet road, there will be less friction between the tyres and the road, the braking distance is longer. 16. What affects a driver s reaction time? Tiredness Drugs/ Alcohol Distractions in the car 17. What is kinetic energy? Every moving object has kinetic energy (sometimes called movement energy). The more mass an object has, and the faster it is moving, the more kinetic energy it has. Kinetic energy (j) = ½ x mass (kg) x speed 2 (m/s) 18. How do you work out work done? Work done (j) = Force (n) x distance moved in the direction of the force (m) 19. What is gravitational potential energy? Any object that is raised against the force of gravity stores gravitational potential energy. For example, if you lift a book up onto a shelf, you have to do work against the force of gravity. The book has gained gravitational potential energy. 20. What is elastic potential energy? Elastic objects such as elastic bands and squash balls can change their shape. They can be stretched or squashed, but energy is needed to change their shape. This energy is stored in the stretched or squashed object as elastic potential energy. 21. What is a conservation of momentum? So long as no external forces are acting on the objects involved, the total momentum stays the same in explosions and collisions. We say the momentum is conserved 22. How do you work out momentum? Momentum (kgm/s) = Mass (kg) x Velocity (m/s) 23. Momentum has both size and direction. True or false? True 24. How do you calculate the change of momentum? Force = Change in momentum / Time taken for that change Change in momentum =force x Time taken foe that change 25. What happens to the momentum of collisions and explosions? The total momentum in an explosion or collision stays the same. 26. What is static electricity?

3 Static electricity is a charge that is not free to move. This causes the charge to build in one place and it often ends with a spark or shock when they do finally move. 27. What happens when you rub 2 insulating materials together? Some insulating materials become electrically charged when they are rubbed together, electrons will be scraped off one and placed on the other. They leave with a positive static charge on one and a negative static charge in the other. 28. What happens when like charges meet? Charges that are the same repel, while unlike charges attract. 29. What is the current? Current is the flow of electricity, no current can flow if the circuit is broken, for example, when a switch is open. 30. What is the potential difference? The potential difference is the voltage of an electrical appliance. Batteries and cells provide the voltage. The voltage is energy that pushes the electrons. 31. What is resistance? Resistance is measured in ohms. The total resistance of a series circuit is the sum of the resistances of the components in the circuit. 32. How are the above connected in an equation? V=IR Potential difference (V) = Current (A) x Resistance (ohms) 33. How is static electricity used? Electrostatic precipitators, photocopiers and laser printers make practical use of electrostatic charges.

4 34. Memorise the symbols of the components in a circuit. 35. What does a graph for a current PD for a resistor at a constant temperature look like? A) A filament lamp. B) a diode A filament lamp 36. Compare the differences between a series circuit and a parallel circuit. Series Circuit ~ the same current flows through all the components. ~ The voltage is shared between the components. Parallel Circuit ~ each component is separately connected ~ If you remove or disconnect one of them, it will not affect the others. ~ All the components get the same P.D ~ The current depends on the resistance of the component. 37. What is the difference between a alternating and direct current? If the current flows in only one direction it is called direct current, or d.c. Batteries and cells supply d.c. electricity, with a typical battery supplying maybe 1.5V. If the current constantly changes direction, it is called alternating current, or a.c. Mains electricity is an a.c. supply, with the UK mains supply being about 230V. It has a frequency of 50Hz (50 hertz), which means it changes direction and back again, 50 times a second. 38. What is frequency? The frequency of a wave is the number of waves produced by a source each second. It is also the number of waves that pass a certain point each second. The unit of frequency is the hertz (Hz). 39. How do you determine the frequency and period from an oscilloscope diagram? The diagram shows an oscilloscope screen displaying the signal from an a.c. supply.

5 40. Describe the structure of a three pin plug. The features of a plug are: 1- The case is made from tough plastic or rubber, because these materials are good electrical insulators. 2- The three pins are made from brass, which is a good conductor of electricity. 3- There is a fuse between the live terminal and the live pin. 4- The fuse breaks the circuit if too much current flows. 5- The cable is secured in the plug by a cable grip. This should grip the cable itself, and not the individual wires inside it. 41. What is a circuit breaker? The circuit breaker does the same job as the fuse, but it works in a different way. A circuit breaker is an electromagnetic switch that opens and cuts the current off if too much current passes through it. 42. Why are metal cased appliances earthed? Many electrical appliances have metal cases, including cookers, washing machines and refrigerators. The earth wire creates a safe route for the current to flow through if the live wire touches the casing. You will get an electric shock if the live wire inside an appliance, such as a cooker, comes loose and touches the metal casing. However, the earth terminal is connected to the metal casing so that the current goes through the earth wire instead of causing an electric shock. A strong current surges through the earth wire because it has a very low resistance. This breaks the fuse and disconnects the appliance. 43. What is the power of a device? The power supplied to a device is the energy transfer to it each second. 44. How a power, current and voltage connected? Power supplied (w) = current (a) x potential difference (v) 45. How are PD, charge and energy transformed related? Energy transformed (j) =potential difference (v) x charge flow (coulombs) 46. What is charge and how is it calculated? The rate of flow of charge is the electric current through the appliance. Charge flow (coulombs) = Current (a) x time (s) 47. Describe the Rutherford Marsden experiment. In 1914 Rutherford carried out an experiment where he fired alpha particles at a metal foil, he noticed that most of the alpha particles went straight through the foil, but a few bounced back off the foil.(this was done in a vacuum) 48. What was discovered From this he concluded that; Atom is mainly made up of space There must be a positive dense centre Most of the mass is in the middle 49. What is an isotope? An isotope is an atom with a different number of neutrons and but the same number of protons.

6 50. What is alpha decay and beta decay? When a nucleus emits an alpha or beta particle it changes into another type of nucleus. We say a nucleus reaction has taken place here. In alpha decay a nucleus loses 2 protons and 2 neutrons. An alpha particle is the same size as a helium atom. In beta decay, an electron is emitted, and one of the neutrons turns into a proton. The mass number stays the same but the proton number increases by one. 51. What are the origins of background radiation? 52. What is a chain reaction? Nuclear physics a self-sustaining nuclear reaction in which each fission of an atomic nucleus causes neutrons and energy to be emitted, each collision of neutrons with other nuclei causing a further fission. 53. What are fissionable substances used in a nuclear reactor? Uranium and Plutonium 54. What is nuclear fission? Nuclear reactors use a process called nuclear fission, when an atom with a very large nucleus is bombarded with neutrons; The nucleus splits into 2 smaller nuclei Further neutrons are released which may cause further nuclear fission, resulting in a chain reaction. 55. What is nuclear fusion? Nuclear fusion occurs when 2 nuclei are forced close enough together so that they form a larger nucleus. When this happens energy is released as heat and light. Nuclear fusion occurs in the sun.