Swing

A child weighing 12 kg is sitting on a swing at a distance of 130 cm from the rotation axis. How far away from the rotation (center) axis must sit down his mother weighs 57 kg if she wants to be a swing in balance?

Correct answer:

x =  27.37 cm

Step-by-step explanation:

$$\begin{gathered} m_1=12\text{ kg } \\ {m}_2=57\text{ kg } \\ {l}_1=130\text{ cm } \\ {M}_1=M_2 \\ {m}_1\cdot l_1=m_2\cdot x \\ 12\cdot 130=57\cdot x \\ 57x=1560 \\ x={\displaystyle \frac{520}{19}}\doteq 27.368421=27.37\text{ cm} \end{gathered}$$

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