$\mathrm{m\omega}^{2} \mathrm{a}=\mathrm{m} \times(2 \pi \mathrm{f})^{2} \mathrm{a}=60 \times\left(2 \pi \times \frac{2}{\pi}\right)^{2} \times 0.1 \mathrm{N}$

$=60 \times 16 \times 0.1=96 \mathrm{N}=\frac{96}{9.8} \approx 10 \mathrm{kgf}$ and this

force is towards mean position.

The reaction of the force on the platform away from the mean position. It readuces the weight of man on upper extreme, i.e., net weight $=(60-10) \mathrm{kgf}$

This force adds to the weight at lower extreme position i.e., net weight becomes $=(60+10) \mathrm{kgf}$ Therefore, the reading the weight recorded by spring balance fluctuates between $50$ $kgf$ and $70$ $\mathrm{kgf}$