- Spring, mass, fixed body
Hi. I have a question regarding the above image and want to know whether I am right or not. In the image there is a body with mass m and in the middle of the body there is a spring. The body is pulled upwards and then it hits two fixed rods such that the body cannot move upwards any more. Now the spring is stretched to a certain amount delta_x. Now I know the spring force which is F_s = k * delta_x. The body itself has a reaction force F_m = - F_s pointing in the upward direction. On the other hand gravity still pulls the body downwards: F_g = m*g. All in all the reaction force at each rod is F_rr = (F_m - mg)/2 pointing in the downward direction.
My goal however is to measure the force that is necessary to stretch the spring to the amount delta_x. I can measure the reaction force F_w and it should always equal -F_s independent of the mass of the body. Am I right?