Final answer:
The angle at which Eddy throws the sandbag is the most critical factor in determining whether the sandbag lands on a 4m high post situated 1.3 m away. The angle of launch affects both the horizontal range and the vertical height the sandbag will achieve during its flight.
Step-by-step explanation:
The question seems to involve a situation where a student, Eddy, throws a sandbag aiming for it to land on top of a vertical post. To determine what factor plays a crucial role in ensuring the sandbag lands on the post, we must understand the physics principles behind projectile motion. Aspects such as the angle of launch, the initial velocity, and the height from which Eddy throws the sandbag all contribute to the sandbag's trajectory.
However, the weight of the sandbag is not directly involved in these calculations, assuming we are neglecting air resistance in our model. Also, while the height from which the sandbag is thrown will affect the time it is in the air, it is not the most critical factor in determining if it will land on the post. The time it took for the sandbag to land would be a result of the throw and not a factor that Eddy can directly control before the throw.
The angle at which the sandbag was thrown is the primary determinant for both the horizontal reach (range) and the vertical reach (height) of the sandbag. Thus, the angle is most likely the critical factor Eddy needs to consider to ensure the sandbag lands on the 4m high post 1.3 m away from him.