Motion

• An object in constant motion will remain so, unless acted upon by an unbalanced, external force.
• The acceleration of an object is directly proportional to the force applied and inversely proportional to its mass.
• For every action, there is an equal and opposite reaction. This is the law of conservation of energy.
• vf= vi + at
• s=(vi x t) + 1/2 a t^2
• vf^2 - vi^2 = 2as
• Mass is the same everywhere. Weight is mass x acceleration due to gravity.
• Ek = 1/2 mv^2
• Ep = mgh
• Elastic collision: Total initial kinetic energy is equal to total final kinetic energy.
• Inelastic collision: Some kinetic energy is converted into another type of energy.
• Range of projectile: S horizontal = Vot
• S vertical = 1/2 a t^2
• The horizontal component of an object's velocity is always constant.
• Momentum: p=mv
• Impulse = Force x time (F x t) = change in momentum (m).
• Work = Force x Distance (F = ma).
• Principle of conservation of momentum: Initial momentum = Final momentum.
• Principle of conservation of energy: Energy is always conserved and cannot be created or destroyed.
• Air resistance factors:

  • cross-sectional area
  • speed (more speed=more AR)
  • air density (more particles=more AR)
  • shape (aerodynamics)
  • texture (smooth vs rough)
• Special Relativity:

  Laws of physics are the same for all inertial frames of reference
• Kepler's First Law:

  All planets move in an elliptical orbit
• Kepler's Second Law

  The radius vector drawn from the Sun sweeps equal area in equal time
• Kepler's Third Law

  T^2 is directly proportional to r^3

  T^2=4pi^2/GMr^3
• Orbits:

  Geo: orbits over one point, same direction as Earth

  Polar: goes over North and South poles, weather and survelliance

  Launch: same direction as spin on Earth, velocity helps launch orbit, therefore cheaper
• If a satellite is too high then it will not be confined to Earth's gravity, but if it is too low then it will fall back down to Earth
• Newton's Universal Law of Gravitation: Every particle in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of their distance. F=G x m1m2/r^2
• Forces causing Centripetal acceleration:

  Tension: attached in order to provide a force

  Frictional: held in means of a friction 'grip' with a horizontal surface to maintain a circular path

  Normal: is frictional force but without a horizontal surface, it is banked instead

  Gravitational: the mass or field of another object exerts a force to maintain a circular path