Question

when a projectile is released, why is there a change in speed in one dimension but not the other? (1 point)
a projectile only moves in two dimensions because it is thrown.
there can be only one force acting on an object at a time.
the force of gravity only acts in a downward direction.
a projectile only moves in one dimension.

Explanation:

In projectile - motion, the horizontal and vertical motions are analyzed separately. The force of gravity acts vertically downward. There is no horizontal force (neglecting air - resistance). So, the speed changes in the vertical dimension due to gravity, while the horizontal speed remains constant (in the absence of non - conservative forces like air resistance).

Answer:

The force of gravity only acts in a downward direction.