Newton's three laws/Friction and Drag/Pendulum experiment

• What is Newton's First Law?

  Law of Inertia: Everybody continues in its state of rest, or of uniform motion in a straight line, unless it is compelled to change that state by forces acting upon it.
• What is Newton's Second Law of Motion?

  The acceleration produced by a particular force acting on a body is directly proportional to the magnitude of the force and inversely proportional to the mass of the body.
• What is Newton's Third Law?

  For every action, there is an opposite and equal reaction.
• What are the two things friction depends on?

  1. The normal force that acts between two surfaces.
  2. The type of surfaces that are in contact.
• Define drag.

  Drag is a type of friction that is caused by the movement of an object through a fluid (gas or liquid).
• What is the Gravitational constant equal to?

  G= 6.67 x 10^-11
• What does gravity depend on?


  M and m stand for the two masses.

  d stands for the distance between the masses.

  G is a constant called the Gravitational constant.

  
• What are the four factors that drag depends on?

  
  

  Cd is a constant value that can only be determined through measurement.

  p is the fluid density that measure how tightly packed the fluid is.

  A is the surface area of object.

  v2 is the square of the velocity.

  
• How does drag depend on the drag coefficient?

  It is different for each different object/fluid pairing. It depends on the shape/streamlining of the object and on its surface type.
• How does drag depend on fluid density?

  The drag effect of honey is far greater than that of water, which in turn has a greater effect than air. This is due to the differing fluid densities.
• How does drag depend on surface area?

  The greater the surface area of a moving object, the more collisions interactions with the fluid particles, which causes a greater drag force.
• How does drag depend on velocity?

  The faster an object goes the more collision interactions and the greater drag force. The velocity has a significant effect on the drag force as can be seen by the squared factor.
• Fill in the blanks

  A) Zero KE, maximum PE

  B) Zero KE, maximum PE

  C) Maximum KE, Zero PE

  D) h

  E) h

  
• An ideal pendulum does not lose any energy to its surroundings. The total energy is always the same.

  At any point during the swing KE + GPE is always equal to the total energy.

  
• In reality a freely swinging pendulum will lose energy to its surroundings. This loss is caused mainly by air resistance (ie. energy is transferred to the air as the pendulum moves through it).

  
• What is the difference between energy transfer and energy transformation?

  An energy transformation involves energy changing form from one type to another.  For example, when you turn on a light switch, electrical energy changes into light energy.  Energy transfer occurs when energy is transferred from one object to another.  For example, when you kick a ball, the kinetic energy in your swinging leg is transferred into the ball.
• What is the law of conservation of mass?


  Energy cannot be created or destroyed, it can only be transferred or transformed.
• What is the difference between an ideal pendulum and a real pendulum? (Explain)


  An ideal pendulum is a pendulum where the total energy in the system remains constant.  The bob will keep swinging back and forth forever.  The pendulums that we typically see in everyday life are real pendulums.  The total energy in the system decreases with each swing as energy is ‘lost’ to the surroundings in the form of heat.  The heat energy is created from friction between the bob and the particles in the air (gases).