WAEC Physics 2023 Paper

Concept:For a body falling freely under gravity, its motion obeys the equation $v^2 = u^2 + 2gh$, where $u$ is initial velocity, $v$ is final velocity, $g$ is acceleration due to gravity, and $h$ is the height fallen.Explanation:The ball is dropped, so the initial velocity is $u = 0$.Just before hitting the ground, the final velocity is $v = 5.0\ \text{m/s}$.Acceleration due to gravity is $g = 10\ \text{m/s}^2$ (downward).Using $v^2 = u^2 + 2gh$, substitute the known values:$$(5.0)^2 = (0)^2 + 2 \times 10 \times h$$$$25 = 20h$$Solving for $h$:$$h = \frac{25}{20} = 1.25\ \text{m}$$The mass of the ball is not needed because the motion depends only on gravity, not on mass.Answer:$H = 1.25\ \text{m}$, which corresponds to option A.