B
Assume north and east as two sides of a right angled triangle. magnitude of the distance is then given by the length of the hypotenuse which is
where a = 1.2 km north
and b = 1.6 km east
magnitude = 2 km
Direction is given by the angle between them, that is atan(a/b) = 36.86 deg north of east = 53.1 deg east of north.
Refer to the diagram attached (created with GeoGebra). Consider the 5 N force in two directions: parallel to the 8 N force and normal to the 8 N force.
The sum of forces on each direction will be the resultant force on that direction:
Apply the Pythagorean Theorem to find the magnitude of the resultant force.
(3 sig. fig.).
The size of the angle between the resultant force and the 8 N force can be found from the tangent value of the angle. Tangent of the angle:
.
Find the size of the angle using inverse tangent:
.
In other words, the resultant force is 17.0° relative to the 8 N force.
