aqa physics gcse - forces

Cards (67)

  • The force on an object is the product of its mass and acceleration.
  • If an unbalanced force acts on an object, it will change direction or speed until equilibrium is reached again.
  • Newton's first law states that if there are no resultant forces acting on an object, it will continue to move at constant velocity or remain stationary.
  • If the net force on an object changes, then the object will change speed or direction.
  • Acceleration can be calculated using the equation F = ma.
  • Forces can be balanced by having equal magnitudes acting in opposite directions (opposite pairs) or unequal magnitudes acting at right angles to one another (couples).
  • A couple is two forces that act perpendicularly to each other with different magnitudes but have the same line of action.
  • When a couple acts on an object, there are no resultant forces along the axis of rotation, so the object does not move.
  • Inertia is the tendency of objects to resist changes in their motion.
  • Weight is the gravitational pull on an object due to gravity.
  • A vector quantity has both magnitude (size) and direction, while a scalar quantity only has magnitude.
  • Forces can act on objects from different directions, resulting in a change in motion.
  • Forces can be represented as vectors using arrows with length proportional to their size and direction indicated by the arrowhead.
  • When two forces act on an object, they produce a resultant force which determines whether the object moves or not.
  • When two forces act together, they form a resultant force which is equal but opposite to the sum of the individual forces.
  • Conduction
    process by which vibrating particles transfer energy to neighbouring particles
  • force and change of momentum
    force = change in momentum / change in time
  • Momentum
    The product of an object's mass and velocity
  • momentum equation
    mass x velocity (p=mv)
  • braking relies on
    Friction between the brakes and wheels
  • factors affecting Braking distance
    -speed
    -how good you're brakes are
    -how good tires are
    -road conditions
  • factors affecting thinking distance
    -speed
    -reaction time, which is affected by drugs, tiredness, alchohol, lack of attention
  • Stopping distance
    Stopping distance = thinking distance + braking distance
  • Equilibrium
    forces in balance
  • newton's third law
    For every action there is an equal and opposite reaction
  • Newton's First Law
    An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
  • Inertia
    The tendency of an object to resist a change in motion
  • newton's second law
    F = ma
  • A zero resultant force means
    no acceleration
  • factors affecting terminal velocity
    shape and area
  • terminal velocity
    the constant velocity of a falling object when the force of air resistance is equal in magnitude and opposite in direction to the force of gravity
  • drag
    resistance by friction from air or water moving over a surface
  • Friction
    A force that opposes motion between two surfaces that are in contact
  • velocity-time graph
    shows how velocity is related to time
  • distance-time graph
    gradient = speed
  • uniform acceleration equation
    final velocity^2-initial velocity^2 = 2 x acceleration x distance
  • uniform acceleration
    constant acceleration
  • Acceleration equation
    final velocity-initial velocity/time
  • Acceleration
    The rate at which velocity changes
  • Velocity
    Speed in a given direction