Summary Grade 12 IEB Physical Sciences - Kinematics Notes (Physics Section A)

Kinematics and mechanics

A. Vectors
Vector representation: Use an arrow

Magnitude
Direction

Vector notation: Put an arrow above symbol

e.g. Velocity = V

Resultant vector:
Biggest when acting in the same direction.
Smallest when acting in opposite directions.
Always between the min and max.

- Graphically
. Tail to head method.



Fnet

- Algebraically
. Use formula.
. Fnet = F1 + F2 + F3

Example:

5,5 N 2,2 N

10,7 N



Method 1: Method 2:

Fnet = F1 + F2 + F3
5,5 N . = 2,2 + (-10,7) + 5,5
. = -3,2
. = 3,2 N down
2,2 N
10,7 N

Fnet

, B. Displacement, Velocity and Acceleration

Position

Symbol: x
Unit: m
Physical quantity: vector

Distance

Symbol: D
Unit: m
Physical quantity: scalar

Displacement

Symbol: Δx
Unit: m
Physical quantity: vector
Formula: xf - xi

Speed

Symbol: V
Unit: m/s
Physical quantity: scalar
𝑡𝑜𝑡𝑎𝑙 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 (𝑚)
Formula: 𝑡𝑖𝑚𝑒 𝑡𝑎𝑘𝑒𝑛 (𝑠)


Velocity

Symbol: V
Unit: m/s
Physical quantity: vector
𝑑𝑖𝑠𝑝𝑙𝑎𝑐𝑒𝑚𝑒𝑛𝑡 (𝑚) ∆𝑥
Formula: 𝑡𝑖𝑚𝑒 𝑡𝑎𝑘𝑒𝑛 (𝑠) = ∆𝑡

m/s to km/h = x 3.6
km/h to m/s =
3.6

Acceleration

Symbol: a
Unit: m/s2
Physical quantity: vector
𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 (𝑚/𝑠) ∆𝑉
Formula: =
𝑡𝑖𝑚𝑒 𝑡𝑎𝑘𝑒𝑛 (𝑠) ∆𝑡