Forces and Motion

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Created by
rami

Cards (12)

  • Speed =
    Velocity =
    Acceleration =
    Speed = distance travelled per unit time
    Velocity = The speed in a given direction
    Acceleration = Change in velocity per unit time
  • What is gradient in a
    Distance time Graph :
    Velocity time graph :
    Distance time Graph:
    • Gradient = velocity
    • Flat line means stationary
    • Curved line means acceleration
    Velocity time graph :
    • Gradient =acceleration
    • Flat line means constant velocity because no change in gradient means no change in speed
    • Area under the graph is distance travelled
  • Scalars:
    Definition
    examples (4)
    Vectors:
    Definition
    examples (4)
    Scalars - have magnitude but no direction
    1. Distance
    2. Speed
    3. Time
    4. Energy
    Vectors have magnitude and direction
    1. Displacement
    2. Velocity
    3. Acceleration
    4. Force
  • Forces:
    Definition -
    Friction -
    Forces can change Speed, Direction or shape of a body and is measured in Newtons
    Friction is the force between two surfaces as they rub against each other causing heating. Air resistance is a form of friction
  • Newton's laws
    First :
    An object has a constant velocity unless acted upon by a resultant force
    Second:
    Force is equal to mass x acceleration
    Third:
    Every action has an equal and opposite reaction
  • Calculation for Weight
    Weight = mass x Gravitational field strength
  • Terminal Velocity
    When the forces are balanced and there is no resultant force so that the object has no acceleration and reaches terminal velocity
  • Thinking Distance:
    What is it?
    Factors which increase thinking distance?
    The time between the driver knowing he has to break and when he actually presses the break
    Factors:
    • Greater speed
    • Alcohol
    • Tiredness It can be reduced through caffeine as it reduces thinking time
  • Breaking distances
    Definition
    Factors
    Stopping Distance
    The travelled distance between pressing the break and the car actually coming to a stop
    Factors which affect breaking distance :
    • The breaks on the car
    • Greater speed, or mass
    • Poor road conditions
    Add together thinking and Breaking Distance
  • Elastic Deformation
    Hooke's law
    Limit of Proportionality
    When the object returns to its original shape after the load has been taken off
    Hooke's Law - Force applied = Spring constant x extension
    Extension is proportional to Spring constant
    When the line stops being linear this is the limit of proportionality
    It stops obeying Hooke's law
    Force is on the Y axis Extension is on the x axis
  • Moments
    What ? How is it measured?
    Equation =
    Equilibrium
    A moment if a force is the measure of its turning effect
    Measured in newton meters
    Moment(Nm) = Force (N) x Perpendicular distance from the Pivot(m)
    Equilibrium - When the total moments clockwise are equal to the total moments anti clockwise , There is no resultant force
  • Momentum
    Equation
    Force =
    Collisions
    Safety
    Momentum is the product of an objects mass and velocity
    Momentum = mass (kg)x velocity(seconds) (measured in kg/s)
    Force = Change in momentum/ time taken
    In a collision Total momentum before = Total momentum after
    Safety features in a car increase the time taken for people in the car to come to rest
    Same momentum over a longer period of time reduces the force
    Seat belt does this by stretching