WAEC Physics 2022 Paper

Concept:The velocity of a freely falling object is independent of its mass and is found using the equation of motion $v^2 = u^2 + 2as$.Explanation:The object is released from rest, so initial velocity $u = 0$.The acceleration is $a = g = 10\ \mathrm{m\,s^{-2}}$.The vertical distance travelled is $s = 30\ \mathrm{m}$.Apply the equation $v^2 = u^2 + 2as$.Substitute the values: $v^2 = 0^2 + 2(10)(30)$.So, $v^2 = 600$.Taking the square root: $v = \sqrt{600} \approx 24.5\ \mathrm{m\,s^{-1}}$.The mass of $50\ \mathrm{g}$ does not affect the result.Answer:The velocity of the object at point B is $\mathbf{24.5\ \mathrm{m\,s^{-1}}}$.Correct option: D.