Question

what is the resultant of combining a force vector of 39 newtons backward with another force vector of 42 newtons backward?
3 newtons backward
3 newtons forward
81 newtons forward
81 newtons backward

Explanation:

Step1: Identify force directions

Both forces are backward.

Step2: Add the magnitudes

Since the directions are the same, we add the magnitudes of the two force - vectors. Let \(F_1 = 39\ N\) and \(F_2=42\ N\). The resultant force \(F = F_1 + F_2\).
\[F=39 + 42=81\ N\]
The direction is the same as the original forces, which is backward.

Answer:

81 newtons backward