ElectroMag

• What is the origin of the word "electric"?

  It comes from the Greek word "electron"
• What materials are good for demonstrating electrostatics?

  Plastic rods and fur
• What does electrostatics refer to?

  Interaction between electric charges at rest
• What are the applications of electrostatics?

  • Operation of laser printers
  • Various technologies in electronics
  • Static electricity demonstrations
• What is the conservation of charges principle?

  The algebraic sum of charges is constant
• What is the natural unit of charge?

  The magnitude of charge of an electron or proton
• What do conductors do?

  Permit electric charge and heat to pass
• What do insulators do?

  Do not permit electric charge and heat to pass
• What is Coulomb's Law related to?

  The electric force between point charges
• What is induction in the context of electric charge?

  Transfer of excess electrons between materials
• What are induced charges?

  Excess charges separated during induction charging
• How many electrons correspond to one Coulomb of charge?

  About 6x10⁸ electrons
• What is an electric field?

  A field of force from charged objects
• What does an electric field measure?

  The electric potential difference between two points
• How is an electric field mathematically described?

  As a vector field indicating force direction
• What does an electric field exert on a positive charge?

  Force that influences its behavior
• What are the key concepts of electric fields at a point charge?

  • Electric field strength decreases with distance
  • Direction of the field is away from positive charges
  • Direction of the field is towards negative charges
• What is a vector?

  A quantity with magnitude and direction
• How is a vector different from a scalar?

  A vector has direction; a scalar does not
• How is a gravitational force represented as a vector?

  By its magnitude, unit, and direction
• What does the length of an arrow represent in a vector?

  The magnitude of the vector
• What is the standard reference frame used for vectors?

  A standard (x,y) reference frame
• What direction does the +x axis represent?

  East
• What direction does the -y axis represent?

  South
• How is vector direction conventionally measured?

  From the x axis of the frame of reference
• How can the direction of a vector be described mathematically?

  Using angles measured counterclockwise from East
• What happens when a vector is multiplied by a scalar?

  Magnitude changes, direction remains the same
• What are the steps to add parallel vectors?

  1. Place vectors head to tail
  2. Measure resultant vector
  3. Add magnitudes if in the same direction
  4. Use negative for opposite direction
• If Blog walks 35 m [E] and then 25 m [E], what is his overall displacement?

  60 m [E]
• If Blog walks 35 m [E] and then 25 m [W], what is his overall displacement?

  10 m [E]
• What is the process for adding perpendicular vectors?

  1. Draw vectors at right angles
  2. Use Pythagorean theorem for magnitude
  3. Use trigonometry for direction
• What is the overall displacement if Blog walks 30 m [N] and then 40 m [E]?

  50 m [37° N of E]
• How do you add multiple vectors using the method of components?

  1. Resolve each vector into x and y components
  2. Add all x components together
  3. Add all y components together
  4. Use Pythagorean theorem for resultant
• What is the resultant displacement of three vectors: 3 m [45° N of E], 6 m [N], and 5 m [30° N of W]?

  11 m [102°] OR 11 m [78° N of W]
• What are the formulas for determining components of a vector?

  • \( \text{x component} = S \cdot \cos(\Theta) \)
  • \( \text{y component} = S \cdot \sin(\Theta) \)
• How do you resolve a vector of 15.2 m [27° N of E] into components?

  x = 13.5 m, y = 6.90 m
• What is the process for solving vector problems?

  1. Sketch a diagram
  2. Resolve vectors into x and y components
  3. Add components
  4. Use trig to find resultant length and direction
• What are the x and y components of Blog's walk of 55 m [42° S of E]?

  x = 40.9 m, y = -36.8 m
• What are the x and y components of Blog's walk of 75 m [185°]?

  x = -74.7 m, y = -6.54 m
• What are the x and y components of Blog's walk of 62 m [78° N of W]?

  x = -12.9 m, y = 60.6 m