Answer:
![h = 18.75 m](https://img.qammunity.org/2020/formulas/physics/college/nshyuee2r6mk2ekoekohnpbpoaquxquhdc.png)
Now when it will reach at point B then its normal force is just equal to ZERO
![N_B = 0](https://img.qammunity.org/2020/formulas/physics/college/mh1iise58gfxkar6wnkean8y56byvg9ny9.png)
![F_n = 1.72 * 10^4](https://img.qammunity.org/2020/formulas/physics/college/rbr5xgoetmidzsl8yaerrhola5crhhhi82.png)
Step-by-step explanation:
Since we need to cross both the loops so least speed at the bottom must be
![v = √(5 R g)](https://img.qammunity.org/2020/formulas/physics/college/iyanx2gpmrm8f08tj7e4pc4gm7ivzwdyl5.png)
also by energy conservation this is gained by initial potential energy
![mgh = (1)/(2)mv^2](https://img.qammunity.org/2020/formulas/physics/middle-school/1ek6f4hakzlj6dy109xhmxtx4n4wjp2p73.png)
![v = √(2gh)](https://img.qammunity.org/2020/formulas/physics/middle-school/s1pl6sgihodp2uhjy5jv5lpgki75wcufir.png)
so we will have
![√(2gh) = √(5Rg)](https://img.qammunity.org/2020/formulas/physics/college/9g2uki3qdlayvc8xw6n9q092ewmte0t5u8.png)
now we have
![h = (5R)/(2)](https://img.qammunity.org/2020/formulas/physics/college/gtr3xyhbr3qhhuzqwen0q9pzs6mf69psb4.png)
here we have
R = 7.5 m
so we have
![h = (5(7.5))/(2)](https://img.qammunity.org/2020/formulas/physics/college/4mup0dcghymiz6akj6hadv5gbxw88v77tr.png)
![h = 18.75 m](https://img.qammunity.org/2020/formulas/physics/college/nshyuee2r6mk2ekoekohnpbpoaquxquhdc.png)
Now when it will reach at point B then its normal force is just equal to ZERO
![N_B = 0](https://img.qammunity.org/2020/formulas/physics/college/mh1iise58gfxkar6wnkean8y56byvg9ny9.png)
now when it reach point C then the speed will be
![mgh - mg(2R_c) = \frac{1}{2]mv_c^2]()
![v_c^2 = 2g(h - 2R_c)](https://img.qammunity.org/2020/formulas/physics/college/os3ctfzlh249pkwe4sigmxit09o1lun4wt.png)
![v_c = 13.1 m/s](https://img.qammunity.org/2020/formulas/physics/college/xuzpqr3eiz0a1es5zcl6k0784pssskdhe3.png)
now normal force at point C is given as
![F_n = (mv_c^2)/(R_c) - mg](https://img.qammunity.org/2020/formulas/physics/college/xkdxss07ig2763hn7tkcwfk2xflcexfk54.png)
![F_n = (700* 13.1^2)/(5) - (700 * 9.8)](https://img.qammunity.org/2020/formulas/physics/college/xbb9qsoce14wt40k9vgt4wia2yy44pi1fn.png)
![F_n = 1.72 * 10^4](https://img.qammunity.org/2020/formulas/physics/college/rbr5xgoetmidzsl8yaerrhola5crhhhi82.png)