SPS SPS SM Pure 2023 June — Question 15

Exam BoardSPS
ModuleSPS SM Pure (SPS SM Pure)
Year2023
SessionJune
TopicLaws of Logarithms

15. The resting metabolic rate, \(R \mathrm { ml }\) of oxygen consumed per hour, of a particular species of mammal is modelled by the formula, $$R = a M ^ { b }$$ where
  • \(M\) grams is the mass of the mammal
  • \(\quad a\) and \(b\) are constants
    1. Show that this relationship can be written in the form
$$\log _ { 10 } R = b \log _ { 10 } M + \log _ { 10 } a$$ \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{f953fd1c-447f-4e97-a42a-5264c053fda0-30_700_901_1005_667} \captionsetup{labelformat=empty} \caption{Figure 3}
\end{figure} A student gathers data for \(R\) and \(M\) and plots a graph of \(\log _ { 10 } R\) against \(\log _ { 10 } M\)
The graph is a straight line passing through points \(( 0.7,1.2 )\) and \(( 1.8,1.9 )\) as shown in Figure 3.
  • Using this information, find a complete equation for the model. Write your answer in the form $$R = a M ^ { b }$$ giving the value of each of \(a\) and \(b\) to 3 significant figures.
  • With reference to the model, interpret the value of the constant \(a\)