displacement is 4 km in north direction.
Step-by-step explanation:
we are given
A runner traveled 15 kilometers north first
then backtracked 11 kilometers south
we have to find displacement=d=?
assume that east side represents +ve x- axis(horizontal)
and
north represent +ve y - axis (vertical)
we can take x-axis (horizontal) as i
and y-axis (vertical) as j.
Displacement = 15 j -11 j = 4 km north