Martin took part in a 60 metre race - Junior Cycle Mathematics - Question 9 - 2017

By looking at the graph at $t = 16$ seconds, the corresponding distance travelled is 40 metres.

Martin’s slowest section is section A, as it has the least slope on the graph.

During section A, the distance travelled is approximately 10 metres over 6 seconds. Therefore, Martin's speed is calculated as: $ext{Speed} = \frac{10 \text{ m}}{6 \text{ s}} \approx 1.67 \text{ m/s}$

The radius of the wheel is half of the diameter: $\text{Radius} = \frac{70 \text{ cm}}{2} = 35 \text{ cm}$

The perimeter $P$ of the wheel is calculated using the formula: $P = 2\pi r = 2\pi(35) \approx 219.9 \text{ cm}$ Rounding to the nearest centimetre gives 220 cm.

First, convert the distance from metres to centimetres: $60 \text{ m} = 6000 \text{ cm}$

Next, divide the total distance by the perimeter of the wheel: $\text{Number of turns} = \frac{6000 \text{ cm}}{220 \text{ cm}} \approx 27.27$ Thus, the wheel turned fully approximately 27 times.