Consider a spring attached at one of its ends to a fixed support and at other end to a box, which rests on a smooth floor as shown in the figure. Denote mass of the box by m, force constant of the spring by k and acceleration due to gravity by g. The box is pushed horizontally displacing it by distance x towards the fixed support and held at rest.
(a) Draw free body diagram of the box.
(b) Find force exerted by hand on the box.
(c) Write all the third law action-reaction pairs.