• Exercise 1
Trajectory is given parametrically: ri = [ cos(t), sin (t),t]
F= m*(d power 2 r/ dtpower 2)
Calculate Force Fi
• Exercise 2
Energy of a covalent bond is approximated as: Vb (rij) =1/2 k [( rij-bij)]power2
Calculate the force acting on atoms as a function of interatomic distance.
exercise 2. It seems to me you have typed the energy funcion incorrectly, and I do not know what rij, bij are.
But force will be the negative derivative of the potential energy funcion, and if you are looking for stablility, then you need to find maxima/minima on the force function.
exercise 1. I do not understand your terms, such as d power 2 r, and dtpower2.