Module 2.1: Describing Motion: Kinematics in One Dimension - Vocabulary

Vocabulary flashcards covering key kinematics concepts from the notes.

Kinematics

The branch of mechanics that describes the motion of objects, including position, velocity, and acceleration.

Straight-line motion

Motion along a single line (one-dimensional motion).

Particle

An object treated as a point where all points move in the same direction at the same speed.

Position

The location of an object at a given time (x(t)).

Displacement

The change in position from the starting point to the current point; a vector that can be positive or negative and is independent of the path taken.

Distance

The total length of the path traveled; a scalar quantity that is always nonnegative.

Delta (Δ)

The symbol used to denote change in a quantity.

Positive displacement

Displacement value greater than zero, indicating motion in the +x direction.

Negative displacement

Displacement value less than zero, indicating motion in the -x direction.

Velocity

Speed with direction; the rate of change of position; a vector; units m/s.

Speed

Rate of motion without regard to direction; the magnitude of velocity; a scalar; units m/s.

Average velocity

Displacement divided by elapsed time; the slope of the position vs. time graph; includes direction.

Instantaneous velocity

Velocity at a specific moment; the limit of average velocity as the time interval approaches zero.

Position-time graph

Graph of position x(t) versus time t; its slope equals velocity.

Acceleration

The rate of change of velocity; a vector; units m/s^2; in 1D, direction is indicated by the sign (+ or -).

Instantaneous acceleration

Acceleration at a specific moment; the limit of average acceleration as the time interval approaches zero.

Velocity-time graph

Graph of velocity v(t) vs. time t; the slope of this graph is acceleration.

Deceleration

Acceleration opposite in direction to the velocity, causing a decrease in speed.

Not moving

Situation where velocity is zero (v = 0); the slope of the position-time graph is zero.

Constant velocity

Velocity that does not change with time; position-time graph is a straight line with constant slope.

Vector

A quantity with both magnitude and direction (e.g., velocity, acceleration).

Scalar

A quantity with magnitude only, no direction (e.g., distance, speed).

1D sign convention

+x is to the right/up and -x is to the left/down.

Units for velocity

Meters per second (m/s).

Units for acceleration

Meters per second squared (m/s^2).