As shown in the figure, the original length of a spring is 20cm, which is suspended vertically. When the spring is pulled down vertically with 15N force, the spring length is 24cm; if it is erected on a horizontal table and pressed down vertically with 30n force, how long is the spring? (ignoring the self weight of the spring, the spring is always within the elastic limit)

As shown in the figure, the original length of a spring is 20cm, which is suspended vertically. When the spring is pulled down vertically with 15N force, the spring length is 24cm; if it is erected on a horizontal table and pressed down vertically with 30n force, how long is the spring? (ignoring the self weight of the spring, the spring is always within the elastic limit)

According to Hooke's law f = KX: when F1 = 15N: 15 = K (0.24-0.2), the stiffness coefficient of the spring is k = 375n / M; when F2 = 30n: 30 = 375x, the solution is x = 0.08m, so when the spring is pressed downward, the spring length is x = 20-8 = 12 (CM); a: if it is erected on a horizontal table, when the spring is pressed downward with 30n force, the spring length is 12cm