Question

when forces are equal

Answer 1

If two individual forces are of equal magnitude and opposite direction, then the forces are said to be balanced. An object is said to be acted upon by an unbalanced force only when there is an individual force that is not being balanced by a force of equal magnitude and in the opposite direction.

Answer 2

since

f=ma

force depend on mass and acceleration

now condition

mass must be content so it must be equal

acceleration is a vector quantity so it have both magnitude and direction

direction must be different with same magnitude acceleration