Ch. 2 (Exam #1): One-Dimensional Kinematics

Flashcards covering key vocabulary from the lecture on One-Dimensional Kinematics, including definitions of position, distance, displacement, speed, velocity, and acceleration.

One-Dimensional Kinematics

Refers to motion along a straight line.

Vectors

Quantities that have both magnitude (length) and direction.

Distance

The total length of travel; a scalar quantity, always a positive number.

Displacement

The vector change in position of an object.

Δx (Delta x)

Represents the 'change' in displacement, calculated as 'xf - xi' (final position minus initial position). It can be positive, negative, or zero.

Average Speed

A scalar number equal to the total distance traveled divided by the time taken; always positive, without direction.

Average Velocity

A vector quantity that is the displacement divided by the time taken. It has direction and can be positive, negative, or zero.

Instantaneous Speed

A scalar number that describes the instantaneous magnitude of velocity, similar to a speedometer reading.

Instantaneous Velocity

A vector quantity equal to the instantaneous speed with a direction added. On an x vs t plot, it is the slope of the line tangent to the curve at a specific point in time.

Acceleration

The rate of change of velocity, a vector quantity measured in m/s².

Average Acceleration

The change in velocity divided by the change in time (Δv / Δt).

Instantaneous Acceleration

The acceleration at any given moment in time, found by taking the average acceleration for infinitely small time intervals (as Δt approaches 0).

Slope of a velocity vs. time curve

Represents acceleration.

Deceleration

Refers to decreasing speed, which occurs when velocity and acceleration have opposite signs. It is not equivalent to negative acceleration alone.

Constant Acceleration Formulas

A set of four useful equations relating initial position, final position, initial velocity, final velocity, acceleration, and time, used specifically when acceleration is constant.

Acceleration due to gravity (g)

Near Earth's surface, it is roughly constant at 9.81 m/s² directed toward the center of the Earth, affecting all objects equally regardless of mass (ignoring air resistance).

Free Fall

The motion of an object subject only to the influence of gravity, neglecting air resistance. An object is in free fall as soon as it is released.

Inertial Reference Frame

A reference frame where an object at rest stays at rest, and an object in motion continues with constant velocity, unless an external force acts upon it. For objects moving at constant velocity, internal events behave as if the frame were at rest.

Position vs. Time Plot with Constant Acceleration

When acceleration is constant, the position vs. time graph takes the shape of a parabola.