[ilovemath]

When drawing a vector diagram, I have been told to use the tip-to-tail rule

However, as per this attachment, the change in velocity (which is a vector) does not seem to use this rule. indeed change in v (the horizontal line) has magnitude V_B - V_a.

Why is this?

[The Mr Z]

(Original post by ilovemath)
When drawing a vector diagram, I have been told to use the tip-to-tail rule

However, as per this attachment, the change in velocity (which is a vector) does not seem to use this rule. indeed change in v (the horizontal line) has magnitude V_B - V_a.

Why is this?

It is using the tip-tail rule, it's just you're adding the wrong way round.

Tip to tail is for a+b=c with the tails of a and c starting at the origin, and the tip of a and the tail of b coinciding, and the tips of b and c coinciding.

for change in velocity the equation is v_a+dv=v_b and as you can see from your diagram the tip of v_a and tail of dv do coincide

[ilovemath]

(Original post by The Mr Z)
It is using the tip-tail rule, it's just you're adding the wrong way round.

Tip to tail is for a+b=c with the tails of a and c starting at the origin, and the tip of a and the tail of b coinciding, and the tips of b and c coinciding.

for change in velocity the equation is v_a+dv=v_b and as you can see from your diagram the tip of v_a and tail of dv do coincide

oh I see