# A hard vectors question M1

The horizontal unit vectors i and j are direction due east and north respectively.

A mountain rescue post O receives a distress call via a mobile phone from a walker who has broken a leg and cannot move. The walker says that he is by a pipeline and he can also see a radio mast which he believes to be south-west of him. The pipeline is know to run north-south for a long distance through the point with position vector 6i km, relative to O. The radio mast is known to be at the point with position vector 2j km, relative to O.

(a) Using the information supplied by the walker, write down his position vector in the form (ai + bj).

Original post by coconut64
The horizontal unit vectors i and j are direction due east and north respectively.

A mountain rescue post O receives a distress call via a mobile phone from a walker who has broken a leg and cannot move. The walker says that he is by a pipeline and he can also see a radio mast which he believes to be south-west of him. The pipeline is know to run north-south for a long distance through the point with position vector 6i km, relative to O. The radio mast is known to be at the point with position vector 2j km, relative to O.

(a) Using the information supplied by the walker, write down his position vector in the form (ai + bj).

I would say (6i+8i)
Original post by yoyoabc
I would say (6i+8i)

You're right but I don't get where 8j comes from. Thanks
Original post by coconut64
You're right but I don't get where 8j comes from. Thanks

Because the man is exactly south west from the mast, the distance south and west must be the same. As he is 6i across with respect to the mast, he must also be 6j away from the mass and therefore 6i+8j
similar beautiful question with follow up in IYGB Special paper P
Original post by yoyoabc
Because the man is exactly south west from the mast, the distance south and west must be the same. As he is 6i across with respect to the mast, he must also be 6j away from the mass and therefore 6i+8j

But I am confused about where he is standing though, I thought he stands at the point where the line 2j intersects the line 6j... Thanks.
Original post by coconut64
But I am confused about where he is standing though, I thought he stands at the point where the line 2j intersects the line 6j... Thanks.

In order to be where 2j and 6i intersect, the mast would have to be west of the man, not south west as it is in the question
Original post by yoyoabc
In order to be where 2j and 6i intersect, the mast would have to be west of the man, not south west as it is in the question

Okay I will try this question again. Thanks.
Do you still require assistance with this question?
Original post by allofthekingsmen
Do you still require assistance with this question?

Just which past paper it’s from ?