Chapter 8 - Kinematics

Formulas of Motion

v=u+at
v²=u²+2as
s=(t(u+v))/2
s=ut + at²/2
s=vt-at²/2

Displacement (s)

Vector quantity that defines shortest straight-line distance and direction from an object’s initial position to its final position

Distance (d)

Scalar quantity of length of path taken

Velocity

Vector quantity of how fast something is moving and in which direction

Symbol for Initial Velocity

u

Symbol for Final Velocity

v

Speed

Scalar quantity of how fast something is moving

Instantaneous Velocity

The rate of change of displacement per unit time at a single instant in time

Average Velocity

The average rate of change of displacement per unit time over a given period

Acceleration

Vector quantity of rate of change

Resultant Vector

Final vector after adding or subtracting vectors

Position

Location of an object at a certain point in time in respect to the origin

True Bearing

A bearing which uses north as zero degrees with a symbol of °T

Quadrant Bearing

Measures direction of a line as an acute angle from North, South, East or West

Collinear

In line with each other

Scalar

A quantity that is defined by its magnitude (amount or size) and units but no direction

Vector

A object that has both magnitude (amount or size) and direction

Position-time Graph

A graph which plots an object’s position on the vertical y-axis against time on the horizontal x-axis. The slope indicates the velocity and the curves indicate acceleration. The area under it represents absement which is measured in meter-seconds and is how far away an object is from a reference point and for how long.

Displacement-time Graph

A graph which plots an object’s displacement from an initial starting point on the vertical y-axis against time on the horizontal x-axis. The slope indicates the velocity and the curves indicate acceleration. The area under it represents absement which is measured in meter-seconds and is how far away an object is from a reference point and for how long.

Speed-time Graph

A graph which plots an object’s speed on the vertical y-axis against time on the horizontal x-axis. The slope indicates the magnitude of acceleration and the curves indicate changing acceleration. The area under it represents distance which is measured in meters and is the total length of the path traveled regardless of direction.

Velocity-time Graph

A graph which plots an object’s velocity on the vertical y-axis against time on the horizontal x-axis. The slope indicates the acceleration and the curves indicate changing acceleration. The area under it represents displacement which is measured in meters and is how far and in what direction an object is relative to its initial position.

Acceleration-time Graph

A graph which plots an object’s acceleration on the vertical y-axis against time on the horizontal x-axis. The slope indicates the jerk and the curves indicate changing jerk. The area under it represents change in velocity which is measured in meters per second and is how much an object's velocity increases or decreases over time.

Gravitational Constant

G = 9.81m/s²

Speed Formula

Speed = Distance/time

Average Acceleration Formula

Change in Speed/Change in Time

Average Velocity Formula

Change in Displacement/Change in Time

Average Speed Formula

Change in Distance/Change in Time

Average Acceleration

The average rate of change of velocity per unit time over a given period

Gradient

The slope of a graph

Instantaneous Acceleration

The rate of change of velocity per unit time at a single instant in time

Trapezoid Formula

Area = (h(a+b))/2