Question

Need a help !!

physics expect pay attention !!


note : look it's head and tail


thanks you !!

Answer 1

In the first case since the resultant is the vector drawn in reverse order according to the triangular law
therefore: ŕ=à+b

in the second case, the third side is taken in the same order and hence, r+a+b=0

(same order is when all tail meet heads, different order is when the head of one vector touches the head of another vector instead of tail)

Answer 2

in the first picture let the resultant vector be r vector.
the vectors a and b are in one direction that is unidirection so their resultant vector will be the arithmatic sum of their scalar value .hence the resultant vector r=vector a+vector b


in the second case all three vectors are in one direction so resultant vector will be in the same direction but their scalar value will be the negative of the sum of two vectors
r vector=vector a+vector b