Midterm 1 - Test Review
Lectures 1A - 3A (Introductory Material)
1. Proportionality
Proportionality: When two variables have a constant ratio, represented by x ∞ y
(or x = ay, where a is a constant). If one variable increases/decreases by a certain
factor, the other variable increases/decreases by the same factor
Using Ratios to Solve Proportionality Problems
a. Determine the ratio you have and the ratio you need
b. Use “conversion factors” (essentially, proportionality statements) to convert
between quantities and find the ratio you need
Isometric: Same geometry, different size
2. Vectors and Vector Components
Scalars vs. Vectors
a. Scalars - Quantities with magnitude (e.g. temperature, mass)
b. Vectors - Quantities with magnitude AND direction (e.g. velocity, weight)
Vector Components: The “pieces” that result from splitting a vector into its
horizontal (VX) and vertical (VY) components. You can convert from:
a. Vector to Components - VX = VcosΘ, VY = VsinΘ
b. Components to Vector - V = √(Vx2 + VY 2), tanΘ = VY / Vx
When adding vectors using components, add the X and Y components of each
vector together, before using the summative VY and VX values to find (V, Θ) of the
resultant vector
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