How many types of trajectory do we have?

There are generally two main types of trajectories considered in physics problems:

1. Parabolic Trajectory: This is the most common type, observed for projectiles under the influence of gravity alone, neglecting air resistance. Examples include a ball thrown at an angle or a cannonball.

2. Straight-line Trajectory: This occurs when an object moves in a straight line, either at a constant velocity or with constant acceleration. This is seen in vertical free fall (neglecting air resistance) or when an object is pushed horizontally on a frictionless surface.