WAEC Physics 2015 Theory — Question 1

Model answer

(a) A projectile is an object or body launched into the air and allowed to move on its own under the influence of gravity only (e.g. a bullet, a thrown stone, a javelin). (b) The only force acting on a projectile in flight is gravity, which acts vertically downwards. Since gravity has no horizontal component, the horizontal acceleration is zero (g_x = 0), so the horizontal component of velocity (u cosθ) remains constant throughout the flight.