### Kinematics

Each list begins with basic conceptual vocabulary you need to know for MCAT questions and proceeds to advanced terms that might appear in context in MCAT passages. The terms are links to Wikipedia articles.

**Kinematics**

Kinematics is a branch of mechanics which provides the basic tools for describing the motion of objects.

**Acceleration**

Acceleration is defined as the rate of change of the velocity.

**Velocity**

Velocity is defined as the rate of change of the position.

**Motion**

Motion means a continuous change in the position of a body relative to a reference point.

**Speed**

Speed is the magnitude of the velocity.

**Distance**

Distance is a numerical description of how far apart objects are at any given moment in time.

**Displacement**

Displacement is the vector that specifies the position of a point or a particle in reference to an origin or to a previous position.

**Scalar**

A scalar is a simple physical quantity that does not depend on direction, and is therefore not changed by coordinate system rotations.

**Vector**

A vector is a physical quantity characterized by both magnitude and direction.

**Uniform circular motion**

Uniform circular motion describes motion in which an object moves with constant speed along a circular path.

**Free-fall**

Free fall is motion with no acceleration other than that provided by gravity.

**Frame of reference**

A frame of reference is a particular perspective from which the universe is observed, providing a set of axes from which an observer can measure the position and motion of all points in a system.

**Trajectory**

A trajectory is the path a moving object follows through space.

**Position vector**

A position vector represents the location of an object in space in relation to an arbitrary inertial frame of reference.

**International System of Units**

The International System of Units (abbreviated SI) is the world's most widely used system of units.

**Standard gravity**

Standard gravity is the nominal acceleration due to gravity at the Earth's surface at sea level.

**Translational kinematics**

Translational kinematics or linear kinematics is the science in classical mechanics of describing the motion of a point particle.

**Ballistics**

Ballistics is the science of mechanics that deals with the motion, behavior, and effects of projectiles.

**Jerk**

Jerk, jolt, surge or lurch, is defined as the rate of change of the acceleration.

**Snap**

Snap or jounce is the fourth derivative of the displacement vector with respect to time, with the first, second, and third derivatives being velocity, acceleration, and jerk, respectively.

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