# Kinematics

Kinematics is a subsection of the field of classical mechanics that aims to describe the motion of particles. The forces that cause this motion are not considered.

A particle is a point-like mass, i.e. an object of finite mass, occupying an infinitesimal volume. Treating objects as 'point-like' removes complications such as internal stresses and strains. The understanding of the motion of these 'point-like' particles provides a solid grounding for the study of more complex bodies in motion.

Kinematics of the material point, as said by its name, studies the motion of a point-like object.

## Terms to know

Time (Δt)
The duration of an observation or action. We always consider time to be the independent variable in kinematics. This means that in distance-time, position-time and acceleration-time graphs, time is always on the x-axis. Δt = t2 – t1 is the time between some start time t1 and some end time t2. We can define those times any way we like, as is convenient for the situation.
Scalar
A quantity that has only a magnitude (size) and no direction, e.g. 900kg.
Vector
A quantity that has both a magnitude (size) and a direction. e.g. 900 km [West]. To show a quantity is a vector we usually put a half-arrow (→) above that quantity or bold the variable letter (e.g. position can written as a bold p).

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