Equilibrium
4.9 A particle is subjected to three forces: $F_1 = 3i + 5j - 8k$ kN, $F_2 = -2i - 3j + 4k$ kN, and $F_3 = -i - 2j + 4k$ kN. Is this particle in equilibrium?
Explain.
4.10 A particle is subjected to three forces: $F_1 = 3i - aj - 7k$ N, $F_2 = -4i - 2j + bk$ N, and $F_3 = ci - 6j + 4k$ N. Find the values of the scalars a, b, and c such that the particle is in