The downward force of gravity causes displacement of an object, but the force of gravity does not affect the component of motion.
a. negative, horizontal
c. negative, vertical
b. positive, vertical
d. none of the above.

The downward force of gravity causes positive displacement of an object, but the force of gravity does not affect the horizontal component of motion. The answer is D. None of the above. The rule of thumb in calculating for the downward displacement due to gravity follows a positive value because it goes with the direction of the force.