Moderate -0.8 This is a straightforward application of Newton's second law to a lift problem with two scenarios (accelerating up vs down). It requires only F=ma with R-mg=ma or mg-R=ma, then finding the difference 2ma. The calculation is simple (2×84×1.2=201.6N) with no conceptual subtlety or multi-step reasoning required.
2. A passenger in a lift has a mass of 84 kg . The lift starts to accelerate at \(1.2 \mathrm {~ms} ^ { - 2 }\). Find the difference between the two possible values of the normal reaction between the lift floor and the passenger. [0pt]
2. A passenger in a lift has a mass of 84 kg . The lift starts to accelerate at $1.2 \mathrm {~ms} ^ { - 2 }$. Find the difference between the two possible values of the normal reaction between the lift floor and the passenger.\\[0pt]
\\
\hfill \mbox{\textit{SPS SPS FM Mechanics 2021 Q2 [5]}}