In a region of space, the potential energy of the system varies with x as u = α − (βx − γ)2 , where α = 38 j, β = 1.0 j1/2m-1, γ = 17 j1/2, and x is measured in meters. a particle of mass m = 2.5 kg is initially at x0 = 11 m. assume there are no dissipative forces (friction, wind resistance, etc.) in this problem. (a) at what position is the force on the particle zero? (b) what is the potential energy of the system when the particle is at the position that you found in part (a)? is this a point of stable or unstable equilibrium?