Kinematics Notes - Vocabulary Flashcards

Vocabulary flashcards covering key kinematics terms and concepts from the notes.

Kinematics

The mathematical description of motion.

Motion

Change of an object's position or orientation; the path is called its trajectory.

Trajectory

The path along which an object moves.

Motion diagram

An image showing an object's positions at several equally spaced instants in time.

Particle diagram

A simplified representation treating the object as a single point to focus on movement.

Position

Location of an object at a given time; requires an origin (reference point).

Origin (zero position / reference point)

The zero position chosen to define coordinates; its value must be specified.

Reference frame

The observer's point of view used to describe location and velocity; motion is relative to it.

Relative motion

Motion that depends on the observer's frame of reference; e.g., a cup appears to move on a train but rests in the train's frame.

Vector quantity

A quantity that has both magnitude and direction.

Magnitude

The size or amount of a quantity (how much).

Scalar quantity

A quantity that has only magnitude, with no direction.

Distance

The total length of the path traveled; can be larger than displacement.

Displacement

Change in position; final position minus initial; ∆x; a vector; can be negative; path independent.

Speed

How fast an object is moving; a scalar quantity with no direction.

Velocity

Speed with direction; a vector quantity (e.g., 60 mph north).

Acceleration

The rate of change of velocity; can speed up, slow down, or change direction; average acceleration is Δv/Δt.

Uniform motion

Motion at a constant speed; v = Δx/Δt.

Instantaneous velocity

The velocity of an object at a specific instant in time.

SI units for displacement/distance

Meters (m).

SI units for velocity/speed

Meters per second (m/s).

SI units for acceleration

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

SI units for time

Seconds (s).

SI units for mass

Kilograms (kg).

1-D kinematic equations

v = v0 + a t; v^2 = v0^2 + 2 a Δx; x = x0 + v0 t + 1/2 a t^2.

Free fall

Motion with only gravity as acceleration; all masses fall at the same rate (on Earth, g ≈ 9.8 m/s^2).

Acceleration due to gravity (g)

g ≈ 9.8 m/s^2 on Earth; direction downward (often taken as negative in a downward convention).

Air resistance

Friction from air that opposes motion; often ignored in simple free-fall problems.

Terminal velocity

The constant maximum speed reached when drag force balances weight; not reached if air resistance is ignored.

Position vs. Time graph

Plots position as a function of time; the slope gives velocity.

Velocity vs. Time graph

Plots velocity as a function of time; the slope gives acceleration; area under the curve gives displacement; tangent slope gives instantaneous velocity on a v-t graph with acceleration.

Tangential slope

The slope of a line tangent to a curve at a given moment, used to find instantaneous velocity on a v-t graph.