Physics - Motion, forces, and energy (Velocity, Acceleration, and Newton's Laws)

Speed is a scalar quantity representing the distance traveled per unit time: $v = \frac{d}{t}$.

Velocity is a vector quantity that describes speed in a given direction. A change in direction results in a change in velocity even if speed is constant.

Acceleration ($a$) is defined as the rate of change of velocity: $a = \frac{\Delta v}{t}$. It is measured in units of $\text{m/s}^2$.

In a Distance-Time graph, the gradient (slope) represents the speed of the object.

In a Speed-Time graph, the gradient represents the acceleration, and the area under the curve represents the total distance traveled.

Newton's First Law (Inertia): An object remains at rest or continues at a constant velocity unless acted upon by a resultant (net) force.

Newton's Second Law: The acceleration of an object is directly proportional to the resultant force acting on it and inversely proportional to its mass: $F = ma$.

Newton's Third Law: For every action force, there is an equal and opposite reaction force acting on a different body.

Mass is the amount of matter in an object (measured in $\text{kg}$), while Weight is the force of gravity acting on that mass: $W = mg$ (where $g \approx 9.8\text{ m/s}^2$ on Earth).