Which of the following statements are true. l. action and reaction force occur in pair.

II. action and reaction forces act on the same object.

III. action and reaction forces can occur one at a time.

IV. action and reaction forces have the same magnitude.

A. I and II
B. I and IV
C. II and III
D. II and IV

Why does the equilibrium position of the spring change when a mass is added to the spring? will the mass oscillate around the new equilibrium position of the spring or the previous position without a mass attached to the spring? if the equilibrium position of the spring changes by 20 cm (assuming no initial mass) when a mass is added to the spring with constant 4.9 kg/s^2, what is the mass of the object attached to the spring?