Two forces of 5 N and 7 N respectively act on an object when will the resultant of the two vectors be at a maximum?

when they are in the same direction. (collinear)

To find when the resultant of the two vectors will be at a maximum, we need to determine the direction in which the vectors are added.

The maximum resultant occurs when the two forces are in the same direction. In this case, if both forces are acting in the same direction, their magnitudes will simply add up to give the maximum resultant.

So, if the two forces of 5 N and 7 N are both acting in the same direction, their resultant will be the sum of their magnitudes: 5 N + 7 N = 12 N.

Therefore, the resultant will be at a maximum when the two forces are acting in the same direction.