Motion, Forces and Energy - Motion

Distance is a scalar quantity representing the total path length, while Displacement is a vector quantity representing the straight-line change in position from a start point to an end point, denoted as $\Delta s$.

Average Speed is calculated as the total distance divided by total time ($v = \frac{d}{t}$), whereas Velocity is the rate of change of displacement ($v = \frac{\Delta s}{\Delta t}$).

Acceleration ($a$) is a vector quantity defined as the rate of change of velocity. If an object slows down, it experiences negative acceleration, also known as deceleration.

On a Displacement-Time graph, the gradient (slope) at any point represents the velocity. A curved line indicates changing velocity (acceleration).

On a Velocity-Time graph, the gradient represents the acceleration ($a$), and the area under the graph represents the total displacement ($s$).

Uniformly accelerated motion can be described using the kinematic equations (SUVAT), provided that acceleration remains constant.

Objects in Free Fall near the Earth's surface accelerate at a constant rate $g \approx 9.81\,m/s^2$ (often taken as $10\,m/s^2$ in IGCSE) in the absence of air resistance.

Terminal Velocity is reached when the upward force of air resistance equals the downward force of weight ($W = mg$), resulting in a net force of $0\,N$ and zero acceleration.