Summary Grade 12 IEB Physical Science: Kinematics

KINEMATICS




@STUDYNOTESBYM

, A. KINEMATICS
1. VECTORS

VECTOR
A physical quantity that has both magnitude and direction

• Examples: Force, acceleration, displacement, weight

SCALAR
A physical quantity that has magnitude only

• Examples: length, mass, time, temperature

RESULTANT VECTOR
The single vector which has the same effect as the original vectors acting together



EXAMPLES: RESULTANT VECTOR IN ONE DIMENSION
Example 1: Boy A exerts a 60N force east while Boy B exerts a 30N force east. Determine the
resultant vectors



The original vectors are acting in the
𝑅𝑒𝑠𝑢𝑙𝑡𝑎𝑛𝑡 = 60𝑁 + 30𝑁 same direction therefore ADD
= 90𝑁 𝑒𝑎𝑠𝑡


Example 2: A 6000N force is acting right and a 4500N force is acting left. Determine the resultant
vectors
Let right be positive




The original vectors are acting in the
METHOD 1: 𝑅 = 6000 + (−4500) opposite directions therefore
= 1500𝑁 𝑟𝑖𝑔ℎ𝑡 SUBTRACT
METHOD 2: 𝑅 = 6000 − 4500
= 1500𝑁 𝑟𝑖𝑔ℎ𝑡

, EXAMPLE: RESULTANT FORCE IN TWO DIMENSIONS




STEP 1:

Determine the
resultant vector in the
horizontal plane




STEP 2:

Determine the resultant
vector in the vertical
plane




STEP 3:

Resolve the horizontal
and vertical vectors into
a vector triangle to
determine the resultant
vector