Physics 1.1 - 1.5: Linear Motion and Graphing

Vocabulary and core concepts from Physics Lessons 1.1 through 1.5, covering linear motion, scientific claims, graphing, and acceleration.

Scientific Claim

An assertion that is capable of being proved wrong through a test.

Falsifiability

The principle introduced by Sir Karl Popper stating that for an assertion to be scientific, it must be capable of being proven wrong.

Demarcation Problem

The problem of distinguishing real science from pseudoscience or metaphysics.

Scientific Measurement Precision

In science, numbers are measurements rather than perfect numbers; for example, a measurement of "2" can represent a range from $1.5$ to $2.5$.

S.I. Units

The system of units preferred in science, including meters ($m$) for distance, seconds ($s$) for time, and kilograms ($kg$) for mass.

Distance

The total path length traveled by an object, measured in meters ($m$).

Displacement

The change in an object's position, measured in meters ($m$) and includes a positive ($+$) or negative ($-$) sign to indicate direction.

Speed

The distance traveled per unit of time, calculated as $\text{total distance} / \text{time}$. It is a scalar quantity measured in $m/s$.

Velocity

The distance traveled per unit of time in a designated direction ($\text{speed} + \text{direction}$). It is a vector quantity calculated as $\frac{\triangle d}{\triangle t}$.

Scalar

A physical quantity that is described by magnitude (a number) only, such as speed.

Vector

A physical quantity that possesses both magnitude and direction, such as velocity.

Frame of Reference

A fixed point or object used to determine motion by comparison, such as trees, buildings, or the Earth.

Acceleration

The rate of change of velocity over time, defined by the formula $a = \frac{\triangle v}{\triangle t} = \frac{v_f - v_i}{t}$. Its unit is $m/s^2$.

Slope (Position vs. Time Graph)

The value representing the velocity of the object.

Flat Horizontal Line (Position vs. Time Graph)

Indicates that the object's velocity is zero and the object has stopped.

Slope (Velocity vs. Time Graph)

The value representing the acceleration of the object.

Area Under the Curve (Velocity vs. Time Graph)

The value representing the displacement or change in position of the object.

Positive Velocity, Negative Acceleration

Motion describing an object moving to the right while slowing down (e.g., pressing the brake in a car).

Negative Velocity, Negative Acceleration

Motion describing an object moving to the left while increasing speed.

Free Fall

Motion where an object falls under the sole influence of gravity.

Vacuum

A space where air is removed, allowing objects of different masses (like a rock and a feather) to hit the ground at the same time.

Kinematic Formula for Acceleration (from rest)

A formula used to calculate acceleration when initial velocity is zero: $a = \frac{2d}{t^2}$.