Quiz No 2 Solution:

 

Force BA is 100 N in magnitude. Find the magnitude and the components of the projection of this force into the line OB.

 

 

FPROJECTION = (FBA . uOB) uOB

 

FBA = (100) [ (4-(-2)i + 8j -4k ] / (36+64+16)1/2

 

= 55.71i + 74.28j 37.14k

 

UOB = ( -2i +4k) / (4+16)1/2 = - 0.447i +0.894k

 

Then FPROJECTION = (55.71i + 74.28j 37.14k) . (- 0.447i +0.894k) [- 0.447i +0.894k]

 

= 25.97i 51.95k