Forces:Topic 5

  • Created by: Lahlah_8
  • Created on: 24-11-18 12:05
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  • Forces:Topic 5
    • Force Basics: 5a
      • Contact Forces
        • Non-Contact Forces
          • Contact
            • When two objects have to be touching for the force to act
              • Examples: Friction, Air Resistance, Tension in ropes, Normal contact forces.
          • Non-Contact
            • When two objects do not need to be touching order for the force to be acting
              • Examples: Magnetic forces, Gravitational forces, Electrostatic forces.
        • Vector
          • A quantity with both Direction and Magnitude
            • Examples: Force,Velocity, Displacement, Acceleration, Momentum
        • Scalar
          • A Scalar quantity is one with Magnitude and no Direction
            • Examples: Speed, Distance,Mass, Temperature, Time
      • Weight
        • Mass
          • Gravity
            • Makes all things accelerate towards ground.
            • It gives everything weight.
            • Effects:
          • Amountof matter in an object
        • The force acting on an object due to gravity.
        • Measured with a Newtonmeter
      • Resultant Forces
        • With a numberof forces acting at a single point, replace them with a single force
        • Resolving Forces
          • Balanced forces
            • Tip to tail
      • Work Done
        • When a force moves an object throughdistance, energy is transferred and work Is done on the object.
          • WORK DONE(J) = DISTANCE (M) X FORCE(N)
          • Working against a frictional force
        • WORK DONE(J) = DISTANCE (M) X FORCE(N)
      • Gravity,Mass and Weight
        • Weight
          • Mass
            • Gravity
              • Makes all things accelerate towards ground.
              • It gives everything weight.
              • Effects:
            • Amountof matter in an object
          • The force acting on an object due to gravity.
          • Measured with a Newtonmeter
        • WEIGHT (N) = MASS (KG) X GRAV. FIELD STRENGHT (N/KG)
    • Forces and Elasticity: 5b
      • Elastic Objects
        • Elastically deformed
          • Can go back to original shape an length once force Is removed
        • Inelastically deformed
          • Cannot return to original length or shape after force is removed
        • FORCE(N) = SPRING CONSTANT (N/M) X EXTENSION (M)
          • Extension is DirectlyProportional to load of force applied
        • Limit of Proportionality
          • The limit to the amount of force you can apply to an object for the extension to keep increasing proportionally
            • Force- extension graph = curves upwards
            • Extension-force graph = Curves downwards
      • Investigating Springs
        • ELASTIC POTENTIAL (J) = 1/2 X SPRING CONSTANT (N/M) X EXTENSION (M)2
        • Equipment: Spring, clamp, fixed ruler, pointer,hanging mass, masses, weight stand
        • Use W=mg
        • Record at eye level and repeat experiment avoiding any human error (although Random error will occur)
        • Force/ Extension graph =  line with slight curve
        • Changes y/ Changein x = F/E = K
          • Calculating speed
    • Forces and Motion: 5c
      • Accelertion
        • How quickly the velocityis changing
        • ACCELERATION(M/S2)= CHANGE IN VELOCITY(M/S) / TIME TAKEN(S)
        • Uniform acceleration
          • Uniform acceleration is constant acceleration
          • FINAL VELOCITY 2 (M/S) - INITIAL VELOCITY (M/S) = 2 X ACCELERATION(M/S2) X DISTANCE (M)
      • Distance-Time Graphs
        • Motion of something travelling in a straight-line
          • Steeper= faster
            • levelling off = decreasing in speed
          • curves represent acceleration
        • SPEED= DISTANCE / TIME
        • GRADIENT = SPEED
        • Calculating speed
      • Terminal velocity
        • Friction
          • If an object has no force propelling it then friction will slow it down
          • always acts in opositedirection
          • you get friction between two surfaces or an object passingthrougha fluid
        • Drag
          • most resistive forces = air resistance or drag
          • keep object streamlined to reduce any drag = flow over more easily
          • Increasing top speed
            • reducing drag = streamined
            • Increasing power o engine = driving force increases and drag force becomes equal to it
      • Velocity-time graphs
        • Shows objectsotion
        • GRADIENT = CCERELATION
        • curve= changing acceleration
        • downhill = deceleration
        • Distance traveled
          • change in vertical / changes horizontal
          • AREA = BASE X HEIGHT
      • Newton'sFirst Law
        • Newton'sSecond Law
          • Newton'sThird Law
            • when two objects interact, the forces they exert on each other are equal and opposite
            • Equilibrium
              • State which forces are equal and opposite
          • RESULTANT FORCE(N) = MASS(KG) X ACCELERATION (M/S2)
        • if the resultant force on a stationary object is zero, the object remains stationary
        • if resultant force on a moving object is zero, it will carry on at the same velocity
        • if there is a non-zero resultant force on an object, its velocity will change(accelerate in the direction of force)
      • Inertia
        • INERTIAL MASS (KG) = RESULTANT FORCE(N) / ACCELERATION (M/S2)
      • Distance, Displacement, Speed and velocity
        • Displacement
          • Displacement is the distance and direction in a straight-line from n objectsstartingto finish point.
        • Distance
          • Distance is how far an object has moved
        • Speed
          • How fast something is going, no regardsdirection
        • Velocity
          • How fast something is going and in what direction
        • Everyday speeds
          • Walking= 1.5m/s
          • Running = 3m/s
          • Cyling = 6m/s
          • Car = 25m/s
          • Train = 55m/s
          • Plane = 250m/s
      • Investigating Motion
        • Equipment: trolley, hook with mass, masses, pulley and light gate connected to data logger
    • Car Safety and Momentum: 5d
      • Stopping Distnace
        • STOPPING DISTANCE = THINKING DISTANCE + BRAKING DISTANCE
        • Thinking distance
          • distance the vehicle travels during drivers reaction time
          • Brakingdistance
            • Stopping Distnace
              • STOPPING DISTANCE = THINKING DISTANCE + BRAKING DISTANCE
              • Thinking distance
                • distance the vehicle travels during drivers reaction time
                • Brakingdistance
                  • distance the vehicle travels after braking
                  • how fast, quality of brakes, tyres, road surface, good grip
                • How fast, how quick
              • Typical stopping distances
                • 30mph = 9m Think + 14m Brake
                • 50mph = 15m Think +38m Brake
                • 70mph = 21m Think + 75m Brake
            • distance the vehicle travels after braking
            • how fast, quality of brakes, tyres, road surface, good grip
          • How fast, how quick
        • Typical stopping distances
          • 30mph = 9m Think + 14m Brake
          • 50mph = 15m Think +38m Brake
          • 70mph = 21m Think + 75m Brake
      • Reaction Time
        • Ruler-drop test
      • Braking
        • Brakingrelies on frictiion from brakes and wheels
        • Frictioncauses work to be done
        • Estimate:
          • Rearrange V2-U2 = 2as
      • Energy Transfer
      • Momentum
        • MOMENTUM (KGM/S) = MASS(KG) X VELOCITY(M/S)
        • Greatermass = greater velocity= more momentum
        • Conservation of Momentum
          • In a closed system the overall momentum is the same before as it is after

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