Motion in a Straight Line - Physics Lecture 02

Vocabulary-style flashcards covering the definitions and properties of motion, distance, displacement, and average speed/velocity based on the YAKEEN NEET 2.0 physics notes.

Motion

A state observed when a particle's position changes with respect to time.

Rest and Motion

Relative terms that are not absolute and depend entirely on the observer's frame of reference.

Distance

A scalar quantity representing the actual path length travelled by a particle; it cannot be negative, cannot decrease, and is dependent on the path taken.

Displacement

A vector quantity defined as the change in position vector ($\Delta\vec{r} = \vec{r}_f - \vec{r}_i$) or the shortest path between the initial and final positions; it can be positive, negative, or zero.

Position Vector ($\vec{r}$)

A vector used to specify the location of a particle in space, such as $\vec{r} = x\hat{i} + y\hat{j} + z\hat{k}$.

Distance vs. Displacement Magnitude

The principle stating that distance is always greater than or equal to the magnitude of displacement ($\text{Distance} \ge |\text{Displacement}|$).

Turning Point

A location in a particle's path where its velocity is zero ($v = 0$), potentially resulting in a change of direction and making distance different from displacement magnitude.

Average Speed

The total path length (distance) travelled divided by the total time taken ($\frac{\text{Distance}}{\text{time}}$).

Average Velocity

The total displacement divided by the total time taken ($\frac{\text{Displacement}}{\text{time}}$).

Equality of Distance and Displacement

The condition occurring only when a particle moves in a straight line without changing its direction.