A-Level Maths: J2-02 [Vectors: The Direction of a Vector]

[joannawhite]

This video just gave me the lightbulb moment I've been needing with this topic for ages. Thank you so much.

[DaBestAround]

Hi, I'm a bit confused. At 2:06, why do we have to take the angle as anti-clockwise. I understand that the i vector is negative but I'm struggling to get my head around it.

Thanks,

[redroses]

Might be a silly q but, When they ask direction of motion, is it always asking for you to calculate this direction using the velocity, or could you use the displacement or acceleration ? By differentiating/integrating

[R]

how can we find the angle it makes with the direction j?
and also for the anti-clockwise is it w/ direction of i or j? will it be 90+ or - ?
thank you, sir

[friedanoor]

Why do you need to measure it anticlockwise? Does this also apply if you're measuring it with the y-axis?

[LeeLarner]

so if the vector was 12i-10j would it be tan(theta)= -10/12 for that one using the SOHCAHTOA rule

[aisha]

how do you find the bearing of a 3D vector? Do you do it using the formula with the hat thing on a? Many thanks

[SM-dsmh]

do questions generally give you the direction?

[zaksystems]

how would u work out the the reflex angle

[ldenny]

Can you not just use bearings? So for example, say vector A has magnitude 10 on a bearing of 234 degrees. Surely that is the least ambiguous way of doing it?