# Kinematics (Part 1)

Mechanics

Nov 14, 2013 (4 years and 7 months ago)

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Kinematics (Part 1)

What is kinematics?

Kinematics = the study of motion & how to describe it.

Motion = a change in position

Can be…

straight circular

arced back&forth

How to detect / display motion

Motion Diagram

series of images of a moving
object that records position at equal time intervals

Motion is observed based on a motionless object

Can show objects at rest, constant speed, speeding
up or slowing down

How to detect / display motion (cont.)

How can you show objects at rest, constant speed,
speeding up or slowing down?

Particle diagram

shows same thing, easier to draw

At rest (no motion) •

Constant speed (distance stays the same)

• • • • •

Speeding up (distance increases)

Slowing down (distance decreases)

• • • • •

Motion based on Frame of Reference

Motion can / will appear to be different based on
your “Frame of Reference” (f.o.r.)

F.O.R.

one’s point of view

Ex. #1 Motion of the planet Mars (f.o.r. = Earth)

Ex. #2 Motion of the planet Mars (f.o.r. = Sun)

How to describe motion

Once you decide where / when to measure a position
change, you must set up a coordinate system.

Coordinate systems tell you the
origin,

magnitude

and
direction

of the motion. (We’ll discuss further
later)

Origin = zero point

Scalar quantity

describes magnitude (represented
with a letter, Ex. s, m,
°
C)

Vector quantity

describes magnitude and direction
(represented with a letter and arrow, Ex. v )