Introduction:
When a force of constant magnitude and a fixed direction acts on a moving object, it affects the object's path. In this scenario, the object experiences a change in its motion due to the force applied. The resulting path of the object depends on various factors, including the direction and magnitude of the force.

Straight Path:
If the force acting on the object is in the same direction as its initial velocity, the object will continue to move in a straight line. This is known as rectilinear motion. The force acts as a "push" or "pull" in the same direction, maintaining the object's velocity without altering its path.

Circular Path:
If the force acting on the object is perpendicular to its initial velocity, the object will move in a circular path. This is known as circular motion. The force acts as a centripetal force, constantly changing the direction of the object's velocity, while its magnitude remains constant. The object moves in a curved path due to the continuous change in direction caused by the force.

Parabolic Path:
In certain situations, the force acting on the object may not be directly aligned with its initial velocity. This can result in a parabolic path. For example, if an object is projected at an angle to the ground, it experiences an initial horizontal velocity and a vertical gravitational force. The combination of these two forces causes the object to follow a parabolic trajectory.

Conclusion:
In summary, when a force of constant magnitude and a fixed direction acts on a moving object, the resulting path can be either straight, circular, or parabolic, depending on the relationship between the force and the object's initial velocity. If the force is in the same direction as the initial velocity, the object will continue to move in a straight line. If the force is perpendicular to the initial velocity, the object will follow a circular path. If the force has a different direction than the initial velocity, the object's path can be parabolic. The specific path taken by the object depends on the forces acting upon it and the initial conditions of the system.