# Lesson_2__PP__-_Scalars___Vectorsx

Mechanics

Nov 14, 2013 (4 years and 6 months ago)

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Bulletin Board

How many of you have e
-
devices that you can put apps
on?

Example: Stop watch, Accelerometer, ...

Pages 4
-
8 in

Motion

Mechanics

The field of physics in which we study the motion of objects.

Kinematics

Explaining the “what” and the “how” of motion.

Kinematics

10 Km

5 Kg

29 seconds

“math is the language of physics”

~Mr. West

Map of NTCS

office

s
tairs

stairs

We are
here:

Map of NTCS

office

s
tairs

stairs

Start
here:

Use the tiles
on the floor.

Map of NTCS

office

s
tairs

stairs

Origin

Map of NTCS

0

s
tairs

stairs

Origin

Map of NTCS

0

20 M

s
tairs

stairs

Map of NTCS

0

20 M
[N]

s
tairs

stairs

Map of NTCS

0

20 M
[N]

Vector

Map of NTCS

0

20 M

Scalar

When would we want to use a scalar and when would we
want to use a vector?

Scalar

VS

Vector

Vector Application

chrome.angrybirds.com

Example of a scalar and a vector.

Distance

VS

Displacement

Distance

The length of the path taken from one point to another.

Displacement

The change in position of an object.

Tools to measure distance and displacement.

Pedometer

VS

Measuring Tape

Δ

= “change in”

Displacement is the
Δ

position.

Displacement is written
Δ
d

Δ
d = 20 m [N]

Δ
d = 20 m [NE]

+

-

North

South

East

West

Up

Down

Δ
d = 20 m [N]

Δ
d = + 20 m

What if I wanted to drive from
ntcs

to the
Yorkdale

mall?

-
14 Km

Δ
d =
d
f

-

d
i

Δ
d = (
-
14)
-

0

What if I wanted to drive from Scarborough to the
Yorkdale

mall?

-
14 Km

+8 Km

Δ
d =

(
-
14)

(+8)

=
-
22

Δ
d =

(
-
14)

(+8)

=
-
22

What does this

value mean?

Will the value of our distance (scalar: magnitude)
always be the same as the magnitude of our
displacement (vector: magnitude plus direction) in
one direction?

Yes

A

No

B

Will the value of our distance (scalar: magnitude)
always be the same as the magnitude of our
displacement (vector: magnitude plus direction) in
one direction?

Yes

A

No

B

A stone is thrown vertically upward from the
roof of a building. Does the position of the
stone depend on the location chosen for the
origin?

A stone is thrown vertically upward from the
roof of a building. Does its displacement
from where it started depend on the location
chosen for the origin?

Which of the following statements about distance,
displacement, and position are always true?

a)
The displacement of an object is the length of path travelled.

b)
The distance travelled by an object is equal to its change in position.

c)
The position of an object is exactly the same as its displacement.

d)
The distance an object travels can be less than its displacement.

Which of the following statements about distance,
displacement, and position are always true?

a)
The displacement of an object is the length of path travelled.

b)
The distance travelled by an object is equal to its change in position.

c)
The position of an object is exactly the same as its displacement.

d)
The distance an object travels can be less than its displacement.

None are true.. In A & B, switch distance/displacement. C is only true if you
start from the origin. For D, displacement could be negative.

Explain why you get the same resultant displacement if
two displacements are added in the reverse order.