PHYSICS 1 [SEM1Q1] - Kinematics: Fundamental quantities and translational motion

scientific claim

need units, reference frames, and evidence

quantity

number + unit + meaning = ?

“number alone is not physics“

Motion

an object is in motion if it changes its position over time

1. Translational - person running on a track

2. Rotational - earth spinning about its axis

3. Vibrational - back-and-forth motion of pendulum

3 types of motion

uniform motion

If the objects’ velocity remains constant along a line as it covers equal distances and time, irrespective of the duration of time.

the particle model

• The size and shape when rotation or deformation is not important.

• Instead, you track a point representing the object’s position, making a model.

  • The model is useful only if it answers the question well enough.

position

• Concerned only with translational motion

  • Treat the moving object as a point particle

• its location with respect to a chosen reference point

motion

depends on where you measure from

with the context of frame reference

function of time

Represent the position as a

displacement

• Answers “how did position change”

• It compares final and initial positions

• It is vector

formula for displacement

distance

• Tracks path length

• It is scalar

odometer

measures total distance travelled

scalar

Quantity that only has magnitude or can be described by a single number

vector

• Quantity that has both magnitude and direction

• Can be identified by an arrow above the symbol

magnitude

___ of a vector is a scalar quantity and is always positive

1. Parallel vectors

2. Negative vectors

3. Equal vectors

4. Collinear vectors

5. Co-terminal vectors

5 types of vectors

Parallel vectors

two vectors that have the same direction

Negative vectors

vectors that have the same magnitude

Equal vectors

same magnitude and direction

Collinear vectors

they act along the same line

Co-terminal vectors

have a common terminal point

speed

• The distance traveled divided by the time required to cover the distance

• SI: meter per second (m/s)

formula of speed

velocity

• Rate of change of displacement

• Measures speed in a given direction

• An example of a vector quantity

formula for velocity

formula for the average velocity

acceleration

• Rate of change of velocity in a given direction

• If it is positive then we understand its rate of change of velocity to be positive and it could mean that its speed is increasing

• An example of vector quantity

formula for average acceleration

velocity and acceleration signs

velocity and acceleration on graphs :)

Review graphs