WAEC Physics 2022 Paper

Concept:Newton's second law gives the net acceleration, then the equation of motion relates distance to initial velocity, final velocity, and acceleration.Explanation:Net forward force is the difference between the engine force and resistive force:$F_{\text{net}} = 1240\ \mathrm{N} - 800\ \mathrm{N} = 440\ \mathrm{N}$.Acceleration is found using $F = ma$:$a = \frac{440}{1220} \approx 0.36\ \mathrm{m\ s^{-2}}$.Initial velocity is zero: $u = 0$.Final velocity is given: $v = 4\ \mathrm{m\ s^{-1}}$.Use the equation $v^2 = u^2 + 2as$:$4^2 = 0^2 + 2(0.36)s$.$16 = 0.72s$.$s = \frac{16}{0.72} \approx 22.2\ \mathrm{m}$.Answer:B. 22.2 m