A runner traveled 15 kilometers north then backtracked 11 kilometers south before stopping. His resultant displacement was

displacement is 4 km in north direction.

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

Resultant displacement is 4 km north.

Explanation:

Let east represents positive x - axis and north represent positive y - axis. Horizontal component is i and vertical component is j.

A runner traveled 15 kilometers north then backtracked 11 kilometers south before stopping,

So initial displacement, 15 kilometers north = 15 j km

Second displacement, 11 kilometers south = - 11 j km

Total displacement = 15 j - 11 j = 4 j km

Total displacement is 4 km north.