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Forces and momentum 1, Buoyancy, Acabar - Coggle Diagram

- - - - represented by the arrow's direction
    - - represented by the length of the arrow
    - - the type of force acting
      - the objects interacting with cause and effect
  - - - Perpendicular to a surface
    - - Always away from the mass
    - - In the opposite direction to the motion of the mass
    - - Pointed towards the surface of the planet
  - - - the vetor sum of the forces operating on a body
      - When many forces are applied to an object they canbe combined
        
        This produces one overall force
      - The resultant force determines the change in the object's motion
      - Resultant force (also called net force) can combine to produce
        
        unbalanced forces
        
        The combined forces do not cancel out completely, meaning there is a non-zero resultant force on the object
        
        The resultant force is not zero
        
        balanced forces
        
        The combined forces cancel each other out
        
        the resultant force acting on the body is zero
    - - When all forces act in the same plane
      - Resultant force can be found through combining all the vectors
    - - When the forces are not on the same plane
      - Resultant force can be found through resolving vectors
        
        INvolves using pythagoras or trigonometry
- - - - The momentum of an object that is moving in only one dimention
      - liear momentum remains constant unless an external resultant force acts upon the system
      - Equation
        
        p=mv
        
        Momentum (kgms⁻¹)=mass(kg) x velocity((ms⁻¹)
      - Conservation
        
        The total linear momentum before a collision is equal to the total linear momentum after a collision unless the system is acted on by a resultant external force
        
        Momentum before=momentum after
        
        momentum is allways conserved
    - - Momentum is a vector quantity with
        
        direction
        
        magnitude
  - - - J=FΔt
        
        impluse (N)= Resultant external force applied(N) x change in time over which the force acts
      - F=Δp/Δt-->Δp=FΔt
        
        change in momentum= impulse
        
        change in momentum can be used to measure impulse directly
        
        J=Δp=mv-mu
        
        impulse=change in momentum=mass x final velocity - mass x initial velocity
        
        Only used when the force F is constant
        
        Ipulse is allways in the direction of the resultant force
    - - has direction
      - has magnitude
    - - The resultant force ona body is the reate of change in momentum
      - Δp=pf - pi
        
        change in momentum=final momentum-nitial moemntum
        
        F=Δp/Δt
        
        Force=change in momentum/change in time
        
        Used when the mass of the body is not constant
        
        equibalent to F=ma
        
        Can only be used when mass is constant
      - Collision and explosions in one dimension
        
        Collision
        
        Collisions are when two or more moving objects come together and exert a force on one another for a relatively short time
        
        Momentum allways conserved
        
        Kinetic energy not always conserved
        
        only if the collision is elastic
        
        If the collision is inelastic, knetic energy is not conserved
        
        A totally inelastic collision is a special case of an inelastic collision where the colliding bodies stick together and move as one body
        
        In a totally inelastic collision, the maximum amount of kinetic energy is transferred away from the moving bodies and is dissipated to the surroundings
        
        To find out if a collision is inelastic
        
        compare energy before and after the collision
        
        Equation for kinetic energy
        
        2 more items...
        
        Collisions in one dimension
        
        When 2 objects interact on a single straight line
        
        Explosion
        
        when two or more objects that are initially at rest are propelled apart from one another
        
        Explosions in one dimension
        
        Explosions in one dimension (1D) usually involve one stationary object becoming two objects that move away from each other along the same line
        
        Momentum before =0
        
        Kinetic energy is never conserved in an explosion
        
        inelastic
- - - - an object at rest will remain at rest unless acted upon by a resultant force
      - an object moving with a constant velocity will remain moving at that constant velocity unless acted upon by a resultant force
    - - slow down an object
      - change its direction
      - speed up an object
    - - resultant force
        
        The resultant force is, therefore, the vector sum of all the forces acting on the body
        
        Force is a vector quantity with both magnitude and direction
        
        Acceleration
        
        Acceleration is a vector quantity with both magnitude and direction
        
        If the resultant force acts in the direction of an object's motion, the acceleration is positive
        
        If the resultant force opposes the direction of the object's motion, the acceleration is negative
        
        the acceleration will always act in the same direction as the resultant force
  - - - force=mass x acceleration (F=ma)
    - - The acceleration will act in the same direction as the resultant force
      - When an unbalanced force acts on an object, the object experiences a resultant force
    - - The resultant force on an object is equal to its rate of change of momentum
      - This change in momentum is in the same direction as the resultant force
      - equations
        
        momentum=mass x velocity (p=mv)
        
        rate of change in momentum
        
        chane in momentum/change in time= mass x change in velocity/ change in time (Δp/Δt=m x Δv/Δt)
        
        force=mass x change in velocity/change in time( F=m x Δv/Δt)
        
        acceleration= change in velocity/change in time (a= Δv/Δt)
        
        therefore
        
        F=ma
  - - - they must
        
        be the same tyoe
        
        have the same magnitude
        
        act in opposite directions
        
        act on different objects
- - - - reaction force
        
        The normal force F subscript N occurs when an object is supported by a surface
        
        It is the component of the contact force acting perpendicular to the surface that counteracts the body
      - Frictional forces
        
        surface frictionfriction
        
        Surface friction F subscript f is a force that opposes motion
        
        Occurs when the surfaces of objects rub against each other,
        
        Imperfections in the surfaces of the objects in contact rub up against each other
        
        increases thermal energy
        
        slows object down
        
        fluid resistance/ viscous drag
        
        Occurs when an object moves through a fluid (a liquid or a gas) (includes air resitstance)
        
        Fluid resistance, or viscous drag F subscript d, is a type of friction
        
        happens because the object colides with particles of the liquid or gas
        
        heats the object and the fluid
        
        slows down motion
        
        Stoke's law
        
        The frictional force between an object and a fluid which opposes the motion between the object and the fluid
        
        Equation
        
        Fd=6πηrv
        
        Viscuous grag force= fluid viscuocity x radoius of the sphere x velocity of the sphere through the fluid
        
        Viscuocity
        
        The thickness of a liquid/how much it resist flowing
        
        Coefficient of viscuocity
        
        a property of the fluid (at a given temperature) that indicates how much it will resist flow
        
        rate of flow is inversely proportinoal to the coefficient of viscuocity
        
        https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=750/https://cdn.savemyexams.com/uploads/2023/08/1-2-9-stokes-law.png
        
        Drag force at terminal speed
        
        Terminal velocity is directly proportional to the radius of the sphere
        
        Terminal velocity is inversely proportional to the viscosity of the fluid
        
        Frictional forces oppose the motion of an object
        
        they can
        
        prevent a stationary object from moving
        
        Reduce the speed of an object
        
        When friction occurs
        
        energy is transfered by friction
        
        raises thermal energy of objects sorrounding it
        
        Work dona against frictional forces cause their rise in temperature
        
        The surface frictional force always acts in a direction parallel to the plane of contact between a body and a surface
        
        Static and dynamic friction
        
        Static
        
        occurs when a body is stationary on a surface
        
        Static friction will match any push or pull force that acts against it until it can no longer hold the two objects stationary
        
        Not constant
        
        Static friction increases in magnitude until movement begins and dynamic friction occurs
        
        equiation
        
        F f≤ μsFN
        
        frictional force≤coefficient of static friction x normal reaction force
        
        coefficient of statif friction
        
        It is a ratio of the force of static friction and the normal force
        
        The larger the coefficient of static friction, the harder it is to move those two objects past one another
        
        between 0 and 1
        
        Dynamic
        
        When a body is in motion on a surface
        
        Constant
        
        For a constant pushing force, dynamic friction will be constant
        
        Equation
        
        Ff=μdFN
        
        frictional force=coefficient of dynamic frictio x normal reaction force
        
        The coefficient of dynamic friction has similar properties to that of static friction
        
        However
        
        2 more items...
        
        Both of these forms of friction depend on the normal reaction force, FN of one object sitting upon the other
        
        For any given situation, static friction should reach a maximum value that is larger than that of dynamic friction
        
        https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1080/https://cdn.savemyexams.com/uploads/2022/01/2.2.6-Friction-1-1.png
      - tension
        
        Tension F subscript T is a force that occurs within an object when a pulling force is applied to both ends
        
        Occurs when two forces are applied in opposite directions to the ends of an object
    - - The extension of the material is directly proportional to the applied force (load) up to the limit of proportionality
      - Fh=-kx
        
        elastic restoring force (N)=spring constant x extension(m)
        
        Spring constant
        
        a property of the material being stretched and measures the stiffness of a material
        
        The larger the spring constant, the stiffer the material
      - applied with extensoins and compressions
        
        extension
        
        how much an object has increased in length
        
        extension = stretched length − unstretched length
        
        Force extension graph
        
        Each material has a different force extension graph
        
        This depends on how brittle or deductile it is
        
        A material will obey the law up to a certain point
        
        This is shown on its force-extension graph by a straight line through the origin
        
        https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1080/https://cdn.savemyexams.com/uploads/2023/08/1-2-8-force-extension-graph-ib-2025-physics.png
        
        The gradient of the line is the string constant
        
        compression
        
        How much an object has dicreased in length
  - - - electrostatic forc
        
        Electrostatic force F subscript e is the force experienced by charged objects in an electric field which can be attractive or repulsive
      - Magnetic force
        
        Magnetic force F subscript m is the force experienced between magnetic poles in a magnetic field that can be attractive or repulsive
      - gravitational force
        
        Gravitational force F subscript g is the attractive force experienced by two objects with mass in a gravitational field
        
        Weight, on Earth, is the gravitational force of the Earth acting on an object with mass
        
        where
        
        F g = mg (weight= gravitationalforce x mass)
- - - - p=density of the ball
      - V=volume of the ball
      - m=mass of the ball