Vector subtraction help

[catdoc]

>  >     >     >
A+B = A+(-B).    Right ?

Question - carry out the following vector subtractions

A) 24 m East minus 18 m North
B) 48 m North minus 22 m South
C) 13.8 m/s East minus 9.4 m/s North

Pleas show working out or give explanation

[moekamo]

A+B=A-(-B) and A-B=A+(-B)

so for a) 24m east minus 18m north = 24m east plus 18m south

b) 48m north minus 22m south = 48m north plus 22m north

c) 13.8m/s east minus 9.4 m/s north = 13.8m/s east plus 9.4 m/s south

not really sure what your meant to do with these though? are you just drawing the vectors and the resultant vector?

[catdoc]

This question is from Nelson physics 12 pg.7 the question is written as above the answers are

a) 6 m North
b) 70 m North
c) 16.7 m s–1 S56°E

i dont understand how to work them out.

 link to question, page 7 question 3

http://www.mediafire.com/?unwrm1dnzdz

link to answers, chapter 1, set 1A question 3

http://www.mediafire.com/?2nmnzyjt2zw

[moekamo]

are you sure a) isnt: 24 m North minus 18 m North, that would work out as 6m North.

b) well i just didnt simplify it in the last step, 48m north + 22m north= 70m north

c) draw a diagram and use pythagoras to get the hypotenuse of the triangle()
then to get the direction, use trig to get the angle as then the angle relative to south is 90 - theta = 55.74 degrees

[catdoc]

yes sorry it was 24 m north minus 18 m north