Final answer:
The vertical component of a projectile's acceleration remains a constant nonzero value due to the constant force of gravity, which is typically 9.8 m/s^2. The correct answer is that the vertical acceleration is a nonzero constant, while horizontal acceleration is zero, keeping the horizontal velocity constant.
Step-by-step explanation:
For general projectile motion with negligible air resistance, the vertical component of a projectile's acceleration is best described as a nonzero constant. This is due to the acceleration of gravity acting in the vertical direction. Since gravity is a constant force near the surface of the Earth and air resistance is negligible, the projectile experiences a constant acceleration downwards, represented by gravity (g).
Answering the given selections specifically, the correct option is: (a) The vertical component of a projectile's acceleration remains a nonzero constant. Gravity acts only in the vertical direction (downwards) and has a magnitude of approximately 9.8 m/s2 near the Earth's surface. This gravitational acceleration remains constant throughout the motion of the projectile. The horizontal acceleration (ax) is zero; therefore, the horizontal velocity remains constant, as gravity does not affect horizontal motion in this idealized scenario.