Vectors A, b and C are 4 units north, 3 units west and 8 units east, respectively. Describe carefully (a) A x B (b) A x C (c) B x C

[Ans: (a)12 units vertically up (b) 32 units vertically down (c) Zero]


Given:

A = 4 units North
B 3 units West 
C 8 units East 

So, keeping in view the given directions of the vectors
Angle 𝜽 between A and B = 90⁰
Angle 𝜽 between A and C = 90⁰
Angle 𝜽 between B and C = 180⁰


To Find:

(a)  A  B
(b)  A  C
(c)  B  C

Solution: 

(a)  A  B

Here we have 

A  B |A |B| Sin Ө n^ 


 by putting values


A  B =  4 x 3  Sin 90⁰  n^ 


Sin 90⁰ = 1 ]


A  B =  4 x 3  1  1 


A  B =  12 units ------Ans


According to the right-hand rules the direction will be vertically upwards.


(b)  A  C

Here we have 

A  C =  |A |C| Sin Ө n^ 


 by putting values


A  C =  4 x 8  Sin 90⁰  n^ 

 
Sin 90⁰ = 1 ]

A  C =  4 x 8  1 1 


A  C  32 units ------Ans


By right-hand rules, the direction will be vertically downwards.


(c)  B  C

Here we have 

B  C =  |A |C| Sin Ө n^ 


 by putting values


B  C =  3 x 8  Sin 90⁰  n^ 

 
Sin 180⁰ = 0 ]

B  C =  3 x 8  0  1 


B  C =  0 units  -------Ans


************************************
************************************



************************************

Shortcut Links For 


1. Website for School and College Level Physics   
2. Website for School and College Level Mathematics  
3. Website for Single National Curriculum Pakistan - All Subjects Notes 

© 2022-Onwards by Academic Skills and Knowledge (ASK    

Note:  Write me in the comment box below for any query and also Share this information with your class-fellows and friends.