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Fisika kelas XII - Listrik Statis part 1 - Gaya Listrik Statis

BIG Course・2 minutes read

Static electricity involves charges at rest, calculated using the electric force formula and considering the dielectric constant of materials. Complex calculations involving multiple charges are done to determine direction and magnitude of forces between charges, crucial for understanding interactions.

Insights

  • Understanding static electricity involves the flow of electricity at rest between charges, symbolized as q in units like microcoulombs, nanocoulombs, and picocoulombs, with the electric force formula F = k * Q1 * Q2 / r^2 playing a crucial role.
  • Calculations in static electricity involve determining the magnitude and direction of electric force between charges, considering attraction and repulsion, requiring careful consideration of the dielectric constant of materials, and the signs (positive and negative) in force calculations to ascertain the direction of forces.

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Recent questions

  • What is static electricity?

    Flow of electricity at rest between charges.

  • What is the electric force formula?

    F = k * Q1 * Q2 / r^2.

  • How are forces calculated in static electricity?

    By considering attraction and repulsion between charges.

  • What is the dielectric constant?

    Material property affecting the electric force formula.

  • How are multiple charges considered in force calculations?

    By analyzing forces between each pair of charges.

Related videos

Summary

00:00

Static Electricity: Charges, Forces, and Directions

  • Static electricity involves the flow of electricity at rest between charges, with positive and negative charges attracting each other.
  • Charges are symbolized as q, with units in microcoulombs (µC), nanocoulombs (nC), and picocoulombs (pC).
  • The electric force formula in static electricity is F = k * Q1 * Q2 / r^2, with k being the electrical constant (9 * 10^9).
  • The dielectric constant (big k) of the material affects the formula, with air having a dielectric constant of 1.
  • Calculations involve determining the magnitude and direction of the electric force between charges, considering attraction and repulsion.
  • Example calculations include determining the force between charges of different types, converting distances to meters, and calculating the resulting force.
  • When dealing with multiple charges, the forces between each pair of charges must be considered to determine the overall force on a specific charge.
  • The direction of the force is crucial, with positive and negative values indicating the direction towards different charges.
  • The final result of the force calculation determines the direction of the force acting on a specific charge.
  • Understanding the signs (positive and negative) in the force calculation helps determine the direction of the force in relation to the charges involved.

15:09

Calculating Forces Between Charges in Physics

  • F23 is calculated as Q2 * Q3 divided by the distance between charges 2 and 3 squared.
  • The value of charge 2 is -1, and charge 3 is 40 microlomes (40 * 10^-6).
  • The calculation for F23 results in 10 newton.
  • F21 is calculated as Q1 * Q2 divided by the distance between charges 1 and 2.
  • Charges 1 and 2 are 20 and 10 microlomes respectively.
  • The calculation for F21 results in 5 newton.
  • The force on charge 2 is determined by subtracting F21 from F23, resulting in a positive 5 newton force towards charge 3.
  • The direction of the force is crucial in understanding the interactions between charges.
  • When dealing with multiple charges in a straight line, the forces are added or subtracted based on the direction.
  • In a triangular configuration of charges, the forces are calculated based on the distances and charges at each vertex.

29:57

Electric Forces in Right-Angled Triangle Charges

  • The shape is a right-angled isosceles triangle with a base and height of 10 cm each.
  • Charges 2 and 3 are 10 cm apart, as are charges 1 and 2.
  • The forces between charges are denoted as f21 and f23, with f21 being attractive and f23 being repulsive.
  • The electric force between charges can be attractive or repulsive.
  • The formula for the resultant vector force between charges 2 and 3 is f21^ + f23^ + 2 * f21 * f23 * cos θ.
  • The calculated values for f21 and f23 are both 9,000.
  • The force on charge 2 is calculated as 9,000√2 newtons.
  • The formula for the force on charge 1 is F1 = √(f12^2 + f13^2 + 2 * f12 * f13 * cos θ).
  • In a rectangle with four charges, the force on charge 1 is calculated using the same formula.
  • When multiple forces act on a charge, the x and y components are calculated using Sigma FX and Sigma FY, projecting forces onto the axes using Sin and Cos functions.

44:41

Calculating Forces and Directions in Physics

  • Pythagoras' theorem is used to find the slant in a rectangular shape.
  • The principle of Sin theta involves dividing the front by the oblique, while Cos theta divides the side by the oblique.
  • Sin theta is calculated as 3/5 and Cos theta as 4/5 in a given example.
  • The forces on one charge are calculated on the x-axis and y-axis.
  • Calculations are done for F12, F13, and F14 using specific formulas and values.
  • The final result for Sigma FX is 8.37 Newtons.
  • The final result for Sigma FY is 7.16 Newtons, indicating a downward direction.
  • The resultant force is calculated by summing Sigma FX and Sigma FY.
  • The direction of the force is determined using the tangent formula and quadrant analysis.
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