In an experiment to determine the acceleration due to gravity g , the formula used for the time period of a periodic motion is $T=2 \pi \sqrt{\frac{7(R-r)}{5 g}}$. The values of $R$ and $r$ are measured to be (60 ± 1) mm and $(\mathrm{m} \pm 1) \mathrm{mm}$, respectively. In five successive measurements, the time period is found to be $0.52 \mathrm{sw}, 0.56 \mathrm{~s}, 0.57 \mathrm{~s}, 0.54 \mathrm{~s}$ and 0.59 . The least count of the watch used for the measurement of time period is 0.01 s . Which of the following statement(s) is (are) true?