8th Grade Science Study Guide: Motion, Velocity, and Acceleration

Vocabulary flashcards covering core physics concepts including speed, velocity, acceleration, vector and scalar quantities, and their associated formulas and units.

Speed

How fast an object moves. It is a scalar quantity, meaning it only has magnitude (a number value) and no direction.

Scalar Quantity

A quantity that only has magnitude (a number value) and no direction.

Velocity

Speed in a specific given direction. It is a vector quantity with standard SI unit meters per second ($\text{m/s}$).

Vector Quantity

A quantity that has both magnitude (speed) and direction.

Acceleration

The rate at which velocity changes over time, including any change in speed or direction, with standard SI unit meters per second squared ($\text{m/s}^2$).

Velocity Formula

Velocity = Displacement ÷ Time ($v = \frac{d}{t}$).

Acceleration Formula

Acceleration = (Final Velocity - Initial Velocity) ÷ Time ($a = \frac{v_f - v_i}{t}$).

Speeding Up (Positive Acceleration)

A type of acceleration that occurs when velocity and acceleration are in the same direction.

Slowing Down (Negative Acceleration / Deceleration)

A type of acceleration that occurs when velocity and acceleration are in opposite directions.

Changing Direction

A form of acceleration where changing direction changes velocity, even if speed remains completely constant.

Final Velocity ($v_f$)

The ending velocity of an object used in the acceleration formula.

Initial Velocity ($v_i$)

The starting velocity of an object used in the acceleration formula.