The body moves in a uniformly accelerated and rectilinear manner. Which statement about the resultant

The body moves in a uniformly accelerated and rectilinear manner. Which statement about the resultant of all forces applied to the body is correct? 1) not equal to 0, constant in absolute value and direction 2) not equal to 0, constant in direction, but not modulo 3) not equal to 0, constant in absolute value but not in direction 4) equal to 0 or constant in absolute value and direction.

The body moves uniformly and rectilinearly when the resultant of all forces applied to the body is not equal to 0, constant in magnitude and direction.

This follows from Newton’s 2 law, according to which: a = F / m, where F is the resultant of all forces that act on the body, m is the mass of the body.

Since the acceleration a and the resultant of all forces F are vector quantities, the acceleration a is directed in the same way as the resultant F.

In order for the acceleration to remain constant and the resultant must be constant both in absolute value and in direction.