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Fields and Waves. Lesson 2.2. VECTOR CALCULUS - Line Integrals,Curl & Gradient. DIFFERENTIAL LENGTHS. Representation of differential length dl in coordinate systems:. rectangular. cylindrical. spherical. (0,0,h). 1. 1. 2. (0,h,0). (0,0,0). LINE INTEGRALS. EXAMPLE: GRAVITY.
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Fields and Waves Lesson 2.2 VECTOR CALCULUS - Line Integrals,Curl & Gradient Darryl Michael/GE CRD
DIFFERENTIAL LENGTHS Representation of differential length dl in coordinate systems: rectangular cylindrical spherical
(0,0,h) 1 1 2 (0,h,0) (0,0,0) LINE INTEGRALS EXAMPLE: GRAVITY Define Work or Energy Change: (dx & dy = 0) Along
2 LINE INTEGRALS (dx & dy = 0) Along Vectors are perpendicular to each other Final Integration:
LINE INTEGRALS Note: For the first integral, DON’T use Negative Sign comes in through integration limits For PROBLEM 1a - use Cylindrical Coordinates: Differential Line Element Implies a CLOSED LOOP Integral NOTATION:
LINE INTEGRALS - ROTATION or CURL Measures Rotation or Curl For example in Fluid Flow: Means ROTATION or “EDDY CURRENTS” Integral is performed over a large scale (global) However, , the “CURL of v” is a local or a POINT measurement of the same property
Note: We will not go through the derivation of the connection between ROTATION or CURL NOTATION: is NOT a CROSS-PRODUCT Result of this operation is a VECTOR More important that you understand how to apply formulations correctly To calculate CURL, use formulas in the TEXT
ROTATION or CURL Example: SPHERICAL COORDINATES We quickly note that:
ROTATION or CURL , has 6 terms - we need to evaluate each separately Start with last two terms that have f - dependence: 0
ROTATION or CURL 4 other terms include: two Af terms and two Ar terms 0 Example: , because Aq has NO PHI DEPENDENCE THUS, Do Problem 1b and Problem 2
GRADIENT GRADIENT measures CHANGE in a SCALAR FIELD • the result is a VECTOR pointing in the direction of increase For a Cartesian system: You will find that Do Problems 3 and 4 ALWAYS , then and IF