2. LINEAR MOTION How would you describe the motion of a 100m runner? To illustrate his motion we use a velocity time graph and then using the following equations. GraphsGraphs We can calculate speed, velocity and acceleration along with distance and time.

3. UVAST Equations

4. The Physics of sky diving Sky diving from space Sky diving from space Sky diving from space

5. SCALARS AND VECTORS VECTORS  All quantities can be split into scalars or vectors  Scalars have magnitude only and no direction; length, area, volume, speed, time  Vectors have magnitude and direction; force, acceleration, velocity, displacement  Head to Head Head to Head

6. FORCES  What is the physics behind an accelerating spacecraft?  When a spacecraft is speeding up, slowing down or changing direction it must expel gas in the opposite direction to the acceleration. The momentum of the spacecraft i.e. its mass x velocity is equal to but in the opposite direction to the gas.  Rocket Travel Rocket Travel

7. MASS  The Mass of an object is a measure of how difficult it is to accelerate that object.  The Mass of an object is a measure of its Inertia.  (The inertia of an object in turn is a measure of how difficult it is to accelerate it.)  The unit of mass is the Kilogram (kg).

8. MOMENTUM Honda Ad Tyndall Lecture  Momentum (p) is the product of mass and velocity  Unit = kgms -1  The total momentum before an interaction is equal to the total momentum after.  m 1 u 1 + m 2 u 2 = m 1 v 1 + m 2 v 2  The principle of conservation of momentum above is applied directly to snooker or pool

9. Question: What is the momentum of a rugby player with mass of 110kg traveling east at 8m/s ? Answer: p=mv =110 x 8 = 880 kgms -1 east

10.  Two snooker balls of the same mass, moving in opposite directions, collide head on. The pink ball is moving to the right at 5 m/s, the blue is moving at 3m/s. The pink ball is brought to rest by the collision. a) What is the velocity of the blue ball after the collision? b) What is the change in momentum of each ball?

11. a) (movement to the right is +,movement to the left is - ) m 1 u 1 + m 2 u 2 = m 1 v 1 + m 2 v 2 (m)(5)+(m)(-3)=m(0)+(m)(v) 5m- 3m= mv 2m =mv 2=v Velocity after in 2m/s to the right b) Pink ball: Change =after –before = m(0) –m(5) =-5m Change in momentum of pink ball is 5 kgms -1 to the left b) Blue ball: Change =after –before = m(2) –m(-3) =5m Change in momentum of blue ball is 5 kgms -1 to the right

12. FORCE Force (F) is that which can cause acceleration F = ma Acceleration is proportional to force Sony Ad

13.  The Newton is the unit of Force.  Def:  1 newton is the force that gives a mass of 1 kg an acceleration of 1 ms -2  1 N = 1 kgms -2

14.  The weight of an object is the force of the earth’s gravity acting on it  W = mg (W = weight, m = mass, g = acceleration due to gravity)  Mass is constant, Weight changes depending on your position.

15. Newton’s 1 st Law A body will remain at rest or continue moving at constant velocity unless acted upon by an external force.

16. Newton’s 2 nd Law The rate of change of momentum is proportional to the applied force and takes place in the direction of the force

17. Newton’s 3 rd Law To every action there is an equal and opposite reaction

18. From Newton II: Force is proportional to the rate of change of momentum Force  rate of change of momentum F  (mv – mu)/t F  m(v-u)/t F  ma F = k (ma) F = ma

19. Friction Friction is a force that opposes the motion of a body. It allows tyres to grip the road or the soles of your shoes to grip the path.

20.  Diagram Page 96  Initially only force is weight. a>0  As velocity increases air resistance begins to oppose motion. a>0  Eventually speed reached where resistance is equal to force, velocity becomes constant. a=0

21.  APPARATUS : Millisecond timer, metal ball, trapdoor and electromagnet

22. APPARATUS  Set of weights, electronic balance, trolley, ticker-tape timer and tape. DIAGRAM

23. Density Density is defined as Mass per unit Volume The unit of density is the kgm -3 The symbol for density is  (pronounced ‘row’ – same symbol as for momentum – don’t ask!)  = m/V  Phet Phet

24. Pressure is defined as Force per unit Area. The unit of Pressure is the Pascal (Pa) 1 Pascal =1 newton per square metre 1 Pa = 1 Nm -2

25. P =  gh P= pressure  = density g = acceleration due to gravity h = depth in a liquid 1. Pressure increase with depth 2. Pressure acts perpendicular to any surface put in the liquid 3. At a given depth the value of the pressure is the same in all directions

26. Archimedes’ Principle When a body is partly or wholly immersed in a fluid it experiences an upthrust equal to the weight of the fluid displaced (Demonstration)

27. The law of Flotation The weight of a floating body is equal to the weight of the fluid it displaces

28. What is a hydrometer? A hydrometer measures the density of liquids. Density is mass per unit volume. The hydrometer is based on the principle of Archimedes. The less dense the liquid the lower the hydrometer will sink.

29.  Used to find the percentage alcohol in beers, wines and spirits (alcohol is less dense than water)  The density of sulphuric acid in a lead acid battery and hence determine the charge of the battery.  The percentage of fat in milk, and to check that the milk has not been watered down

30. The physics of weather We are surrounded by atmospheric pressure. Pressure is force per unit area. The pressure exerted by the air is roughly 101.3kPa or 1x10 5 Pa at sea level. Variations in this pressure have an effect on the weather. Low pressure gives us cloudy, wet, windy weather. High pressure results in fine, sunny weather.

31. Why does water boil at a lower temperature the higher up you go? The higher you go the less the atmospheric pressure is an the less molecules there are pressing down on the water therefore the water needs less energy to move and will boil at a lower temperature than 100 o C Bed of Nails

32. Boyle’s Law Pressure is inversely proportional to volume for a fixed mass of gas at constant temperature. A good example of Boyle’s law is the use of a syringe. Exp

33.  If the pressure is doubled the volume is halved  If the pressure is trebled the volume is decreased by 1/3  Graph of p against 1/V is straight line through the origin.

34.  For a fixed mass of gas at constant temperature pV =k Where k is a constant  P =pressure  V=volume  K =constant

35. Newton’s Law of Universal Gravitation The force of attraction between two point masses is proportional to the product of their masses and inversely proportional to the square of the distance between them. Orders of magnitude Motion round the earth

36. Moment Moment is the force by the perpendicular distance. The further the distance the bigger the moment

37. A Lever A lever is a rigid body that is free to rotate about a fixed axis A Couple A couple A couple is a pair of equal and opposite forces whose lines of action don’t coincide.

38. Equilibrium If a body is said to be in equilibrium it must satisfy the following; The forces up equal forces down and the forces left equal forces right The sum of the clockwise moments equal the sum of the anticlockwise moments

39. ENERGY All Energy comes from the sun. We make use of the fusion reactions of the sun for our energy. Fusion is a form of nuclear reaction whereby small nuclei combine to form large nuclei giving a lot of energy.

40. ENERGY We define energy as the ability to do work We define work as the product of force and displacement W = F × s

41. Forms of Energy Kinetic Energy is the energy a body has due to its motion

42. FORMS OF ENERGY Potential Energy is the energy a body has due to its position Snowboarding

43. FORMS OF ENERGY Heat Energy is the kinetic energy of its internal particles

44. FORMS OF ENERGY Sound Energy is the energy of vibrating particles in the medium it travels through

45. FORMS OF ENERGY Electrical Energy is the energy as the result of the motion of electric charge

46. FORMS OF ENERGY Chemical Energy is the energy stored within the chemical bonds of molecules

47. FORMS OF ENERGY Nuclear Energy is the energy stored in the nucleus of an atom

48. Principle of Conservation of Energy Energy cannot be created or destroyed but changes from one form to another.

49. Watt is the unit of Power!! All electrical devices have a power rating on them. This allows us to calculate the rate at which work is done or energy is used. The efficiency of the appliance is a measure of how good it is at converting energies without waste.

50. Elasticity Many objects change shape when a force is applied to them, e.g. elastic band. When the force is removed the object may return to its original shape, i.e. object is said to be elastic.

51. Elasticity If the force applied is too great the object remains permanently strained it has exceeded its elastic limit. The force trying to pull the object back into its original position is the restoring force. This force is directly proportional to the displacement.

52. Hooke’s Law Hooke’s law states that when an object is bent, stretched or compressed by a displacement ‘s’, the restoring force ‘F’ is directly proportional to the displacement-provided the elastic limit is not exceeded. F = – k s where k = elastic constant Experiment App  The equation is known as Hooke’s Law (after Robert Hooke (1635- 1703), an inventor, philosopher, architect,...)

53. Simple Harmonic Motion Position O is called the equilibrium position. If pulled beyond O it vibrates up and down. When doing this the particle can be said to be moving in simple harmonic motion. Definition: A body is said to be moving with simple harmonic motion if: 1. Its acceleration is directly proportional to its distance from a fixed point on its path. 2. Its acceleration is always directed towards that point.

54. CIRCULAR MOTION

55. Angles in Radians  We usually measure angles in degrees.  360° = 1 rotation  But it's not the most convenient way to measure angles in circular motion. Radians. The radius of a circle and its circumference are related by the equation  Circumference = 2πr  360° ≡ 2π radians and  180° ≡ π radians Formula  s = rθ  Where:  s = arc length covered  r = radius of the circle  θ = angle in radians

56. Angular Velocity  Angular Velocity is the rate of change of angle with respect to time.  Angular Velocity is measured in radians per second, (rad/s).  The symbol for angular velocity is  (pronounced“omega”).

57. Relationship between Linear Speed (v) and Angular Velocity (  )

58. Centripetal Force The force - acting in towards the centre - required to keep an object moving in a circle is called Centripetal Force.

59. Centripetal Acceleration If a body is moving in a circle the acceleration it has towards the centre is called Centripetal Acceleration.

60. Circular Satellite Orbits

61. Geostationary Satellites  These satellites are stationery over one position of the globe  We know that if we want a satellite to remain over a specific spot on the Earth’s surface it must have the same periodic time as the Earth (24 hours).