**Evans SPH 3U1**

**Physics Grade
11**

**Unit 1: Forces
and Motion**

**Note 6: Motion
in Two Dimensions**

Reference: Chapter 2.1, 2.2

**Vector Direction Notations:**

tail head or tip

1) [N60E] [E30N] some books will also call these the following (but I do not like).......[30 N of E] [60 E of N]

2) [W60S] [S30W] some books will also call these the following (but I do not like).......[30 W of S] [60 S of W]

Note: In words [N60E] reads as "north 60 degrees east"

In words [30 N of E] reads as "30 degrees north of east" (but I will not use this one although you should be familiar with it)

**Adding Vectors:**

Vectors are added tip(head) to tail. The resultant vector is drawn from the tail of the first vector to the head of the last vector. Fig. 3.5 pg.79

**Subtracting Vectors:**

Subtracting is really the same as adding. i.e. Show example

*If you need to add more than
two vectors you should use the component method.............*

**Components:**

Review trig ratios sine, cosine, tangent (overheads)

**Adding with components:**

- Resolve vectors into x (horizontal) and y (vertical) components

- Assign directions

- Add horizontal (x) components

- Add vertical (y) components

- Use pythagorean theorem to find the MAGNITUDE of the resultant i.e.

- Use trig ratio to find the DIRECTION of the resultant

**Example 1: **A student
walks 5.0 km [N30E], then 4.0 km [S40E] and then 2.0 km [W]. What is the
student's resultant displacement?

**Example 2: **If the
student took 2.5 hours for the trip, what was her speed and velocity?

**Adding with Cosine Law and Sine Law:**

Pg 65 #8 (scaled)

Pg 75 #1-3

Pg 75 #4,5,6 (components and cosine/sine law) #7 (components)

Pg 75 #8,9

Handout Motion in 2D