Tractor's 7352

The tractor's rear wheels have a diameter of 1.25 m, and the front wheels have a diameter of 55 cm. What is its speed? How many times does each wheel turn on a 1.5 km track?

Correct answer:

r =  11:25
n₁ =  382
n₂ =  868

Step-by-step explanation:

$$\begin{gathered} d_1=1.25\text{m} \\ {d}_2=55\text{cm}\to \text{m}=55:100\text{m}=0.55\text{m} \\ r=d_2/d_1=0.55/1.25=0.44=11:25 \end{gathered}$$

$$\begin{gathered} s=1.5\text{km}\to \text{m}=1.5\cdot 1000\text{m}=1500\text{m} \\ o=2\pi r=\pi d \\ {o}_1=\pi \cdot d_1=3.1416\cdot 1.25\doteq 3.927\text{m} \\ {n}_1=s/o_1=1500/3.927=382 \end{gathered}$$

$$\begin{gathered} o_2=\pi \cdot d_2=3.1416\cdot 0.55\doteq 1.7279\text{m} \\ {n}_2=s/o_2=1500/1.7279=868 \end{gathered}$$

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