DEVIL PHYSICSTHE BADDEST CLASS ON CAMPUS

IB PHYSICS

TSOKOS LESSON 1-4VECTORS AND SCALARS

Objectives

Describe the difference between vector and scalar quantities and give examples of each

Add and subtract vectors by a graphical technique, such as tail-to-head or parallelogram rule

Objectives

Find the components of a vector along a given set of axes

Reconstruct the magnitude and direction of a vector from its given components

Solve problems with vectors

Introductory VideoWhat are scalars and vectors?

Scalars

Require only a number to represent them

No direction involved

Vectors

Cannot be fully specified without both a number (magnitude) and direction

Represented by an arrow from left to right over the variable

Two vectors are equal only if both their magnitude and direction are the same

A

Examples of Vectors and Scalars

Multiplying a Vector by a Scalar Multiplication of a vector by a scalar only

affects the magnitude and not the direction

3xA

Introductory VideoAdding vectors

Adding VectorsParallelogram Method

A

B

R

Adding VectorsHead-To-Tail Method

A

B

R

Subtracting VectorsHead-To-Tail Method

A

B

R

Adding VectorsHead-To-Tail by Components

A

B

R

Adding VectorsHead-To-Tail by Components

A

B

R

R

xR

yR

Adding VectorsHead-To-Tail by Components

A

B

R

A

xA

yA

B

xB

yB

Trigonometry Revisited

A

BC

x

y

A

Bx

A

B

adj

oppx

C

Ax

C

A

hyp

adjx

C

Bx

C

B

hyp

oppx

o

o

o

1

1

1

tan,tan

cos,cos

sin,sin

Adding VectorsComponent Method

A

A

xA

yA

2.2145sin30

3045sin

2.2145cos30

3045cos

from45,30

o

y

yo

o

x

xo

o

A

A

A

A

xA

Adding VectorsComponent Method

B

B

xB

yB

5.825sin20

2025sin

1.1825cos20

2025cos

from25,20

o

y

yo

o

x

xo

o

B

B

B

B

xB

Adding VectorsComponent Method

R

xR

yR

2.41

6.125.81.21

2.391.181.21

22

222

yx

yyy

xxx

RRR

cba

BAR

BAR

Adding VectorsComponent Method

R

xR

yR

o

x

y

x

y

R

R

R

R

8.17

2.39

6.12tantan

tan

11

Summary: Can you

describe the difference between vector and scalar quantities and give examples of each?

add and subtract vectors by a graphical technique, such as tail-to-head or parallelogram rule?

Summary: Can you

find the components of a vector along a given set of axes?

reconstruct the magnitude and direction of a vector from its given components?

solve problems with vectors?

QUESTIONS?

Homework

#1-17, skip #11 and #15