Explanation

(a) Here, $r = 100m,v = 7ms^{- 1},m = 60kg$
Reading registered= resultant force =?
Two force are acting, weight $mg$ and centripetal force $\frac{mv^{2}}{r}$ at $90{^\circ}$ to each other
$\therefore$ Resultant force $= \sqrt{(mg)^{2} + \left( \frac{mv^{2}}{r} \right)^{2}} = mg\left\lbrack 1 + \left( \frac{v^{2}}{rg} \right)^{2} \right\rbrack^{1/2}$
$= 60 \times 9.8\left\lbrack 1 + \left( \frac{7 \times 7}{100 \times 9.8} \right)^{2} \right\rbrack^{1/2}$
$= 60.075 \times 9.8$ N = 60.075 kg-wt