Sat physics - spark notes

4.1 Vectors
VECTORS ARE USUALLY THE FIRST THING you learn in a physics class, and they’re the first thing you’ll learn here. Vectors are one of the fundamental mathematical tools the physicist uses, and one that is frequently misunderstood or misapplied by students. Generally, there aren’t more than one or two questions on SAT II Physics that test your knowledge of vectors directly, but there are a host of problems—particularly in mechanics—where arriving at the right solution demands a solid grasp of how to apply and manipulate vectors. Even if you feel confident with vectors, we urge you to review this chapter and be absolutely sure you won’t get tripped up on what would otherwise be some easy questions.

4.2 Vector Addition
There are bound to be several questions on SAT II Physics that involve vector addition, particularly in mechanics. The test doesn’t demand a very sophisticated understanding of vector addition, but it’s important that you grasp the principle. That is, you won’t be asked to make complicated calculations, but you will be expected to know what happens when you add two vectors together.
The easiest way to learn how vector addition works is to look at it graphically. There are two equivalent ways to add vectors graphically: the tip-to-tail method and theparallelogram method. Both will get you to the same result, but one or the other is more convenient depending on the circumstances.
Tip-to-Tail Method
We can add any two vectors, A and B, by placing the tail of B so that it meets the tip ofA. The sum, A + B, is the vector from the tail of A to the tip of B.

Note that you’ll get the same vector if you place the tip of B against the tail of A. In other words, A + B and B + A are equivalent.
Parallelogram Method
To add A and B using the parallelogram method, place the tail of B so that it meets the tail of A. Take these two vectors to be the first two adjacent sides of a parallelogram, and draw in the remaining two sides. The vector sum, A