2022-03-15T20:03:21+03:00[Europe/Moscow] af true Vectors vs scalar, What can vector triangles determine?, vector diagrams, Resolving vectors, What is a moment?, Moment equation, When an object is in equilibrium, What is a couple?, moment of a couple equation, Centre of mass, The line of action , How can the centre of mass be found?, When will an object topple?, Newton's first law, Newton's second law, Newton's third law, In projectile motion..., Friction, Drag, Lift, Terminal Velocity, principle of moments, terminal velocity for humans, In a closed system, momentum equation, momentum is conserved, inelastic collsion, Elastic collision, Impulse equation, Impulse, The area under a force-time graph, Power, work done and efficiency equations, When is work done, What is one watt equal to, Density equation, What is density?, <p>Conservation of momentum</p> flashcards
Mechanics

Mechanics

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  • Vectors vs scalar
    Vectors have both a magnitude and a direction Scalar quantities only have a magnitude
  • What can vector triangles determine?
    The resultant vector can determine whether the forces are balanced (with a resultant force or not)
  • vector diagrams
  • Resolving vectors
    Split a vector into its horizontal and vertical components can be resolved using trigonometry or parallelogram method
    Split a vector into its horizontal and vertical components can be resolved using trigonometry or parallelogram method
  • What is a moment?
    The moment of a force about a point is the product of the force and the distance from its line of action to the point
  • Moment equation
    Moment (Nm) = Force (N) x Perpendicular distance (m)
  • When an object is in equilibrium
    The moments on it about a point are balanced Total clockwise moment = total anticlockwise moment
  • What is a couple?
    A pair of equal and opposite parallel forces acting on the same body that do not act in the same line
    A pair of equal and opposite parallel forces acting on the same body that do not act in the same line
  • moment of a couple equation
    Moment of a couple (Nm) = Force(N) x Perpendicular Distance Between Lines of Action (m)
  • Centre of mass
    Where the mass of an object can be considered to be concentrated 
  • The line of action 
    acts from the centre of mass and shows how gravity is acting upon the object
  • How can the centre of mass be found?
    By suspending an object by a pin and then using a plum line to draw on the line of action-where they cross is the centre of mass
  • When will an object topple?
    If he line of action falls outside of the width of the base then the object will topple
  • Newton's first law
    The velocity of an object will not change unless a resultant force acts upon it
  • Newton's second law
    F = ma force in N equals mass in kg times the acceleration in ms^-2
  • Newton's third law
    Every force has an equal and opposite force
  • In projectile motion...
    The horizontal and vertical components are treated seperately. Acceleration is due to gravity, hence only affects the vertical component and is positive if acting with the object and vegative if against it.
  • Friction
    a force that oppoes motion when moving on a soliid
  • Drag
    a force that opposes motion in a fluid, it usually increases with speed
  • Lift
    an upward force created on an object as it moves through a fluid due to the shape of an object
  • Terminal Velocity
    happens when frictional forces equal the driving force, causing equilibrium and zero acceleration
  • principle of moments
    principle of moments states that for a body to be in rotational equilibrium the sum of clockwise moments at any point must be equal to the sum of the anticlockwise moments about that same point
  • terminal velocity for humans
    ~ 240-290km/h
  • In a closed system
    momentum is conserved meaning that the product of velocity and mass is the same before and after occurs in both collisions and explosions
  • momentum equation
    p = mv
  • momentum is conserved
    p1 =p2  m1v1 = m2v2
  • inelastic collsion
    kinetic energy is not conserved  -> so we can work out the change in kinetic energy and hence how much energy is dissipated in other forms change in energy = final kinetic energy - initial kinetic energy
    kinetic energy is not conserved  -> so we can work out the change in kinetic energy and hence how much energy is dissipated in other forms change in energy = final kinetic energy - initial kinetic energy
  • Elastic collision
    kinetic energy is conversed  Final kinetic energy = Initial kinetic energy
  • Impulse equation
  • Impulse
    The change in momentum The produc of force and time
  • The area under a force-time graph
    is impulse
  • Power, work done and efficiency equations
  • When is work done
    when a force is applied across a distance
  • What is one watt equal to
    One joule per second
  • Density equation
  • What is density?
    Density is the mass of a material per unit volume

  • Conservation of momentum

    Total momentum before = total after

  • neutron will rebound / have velocity / momentum to the left

    momentum transferred to the uranium will be greater

    velocity of uranium will be greater