Which of the following equations apply to the horizontal motion (x-direction) of an ideal projectile with g = 9.8 m/s/s (neglecting effects due to the air)?
1) x = v0 * t
2) x = v0 * t + (1/2) * a * t²
3) x = v0 * t + (1/2) * g * t²
4) x = v0 * t + g * t²