# Unit 2 - Chapter 6

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• Created by: AnushaK
• Created on: 13-02-14 17:51
• Ch 6
• Scalars and vectors
• Scalar - magnitude, no direction e.g. distance, time etc.
• Vectors -  direction + magnitude e.g. displacement, velocity etc.
• - line of length proportional to magnitude - arrow to show direction
• In a straight line - add or subtract depending on direction
• Perpendicular vectors - use SOHCAHTOA to find RESULTANT
• AQA EXAMINER's TIP - use a large scale to reduce inaccuracy in measurement- use a sketch for calculations to ensure the right direction of the vectors
• Cross Winds act at 90^ to direction of movement
• Cross Currents act at 90^ to boating/ sailing
• AQA EX TIP - vectors cannot be mixed up, so displacement and forces should not on velocity diagrams
• Cross Winds act at 90^ to direction of movement
• Cross Currents act at 90^ to boating/ sailing
• AQA EX TIP - vectors cannot be mixed up, so displacement and forces should not on velocity diagrams
• Head winds and Tail winds
• Wind velocity will add to or subtract from athlete's velocity
• Air speed and ground speed - V_ground = V_air+V_wind
• Resolving Velocities - splitting a vector into x and y component
• Free-Body Diagrams - shows forces acting on only one object
• Rules : 1. only draw one body 2.do not mark forces +resultant   3. Label clearly, full name or symbols if defined       4. only the tension as pull on the diagram should be marked
• Forces on Free Body Diagram - Weight, Tension, Normal Reaction, Friction or drag, lift=object moves upward with aerodynamic forces, Upthrust = displacing gas or liquid, thrust.
• Lift - shape of aircraft's wing, top surface curved, air flow over top faster, so less pressure above wing = net upward force
• Wind velocity will add to or subtract from athlete's velocity
• Thrust - driving force by pull of propellor or push of jet engine. Jet engine forces exhaust backwards = push aircraft forward
• Drag - resistive force of air = slow aircraft down. Thrust = drag for aircraft flying at constant speed
• Weight = Mass x gravity
• Lift - shape of aircraft's wing, top surface curved, air flow over top faster, so less pressure above wing = net upward force
• Thrust - driving force by pull of propellor or push of jet engine. Jet engine forces exhaust backwards = push aircraft forward
• Drag - resistive force of air = slow aircraft down. Thrust = drag for aircraft flying at constant speed
• Climbing + accelerating = lift > weight and thrust > drag. Resultant forces causes moving up and forward
• Forces can be resolved like velocities - [email protected] overcomes horizontal friction and [email protected] overcomes weight of object to make it move vertically
• Resolving Velocities - splitting a vector into x and y component