Question

there are forces of 75N and 85N on a rock in the opposite direction. find the magnitude of the resultant force ​

Answer 1

Magnitude of vectors are 75 and 85 each.

Since the forces are acting in opposite directions, we have θ = 180°.

So the magnitude of the resultant is,

√(75² + 85² + 2 · 75 · 85 cos 180°)

√(5625 + 7225 - 12750)

√100

I.e., 10 N

Since 85 N force is greater and the forces are in opposite directions, the direction of the resultant is along this force.