Answer to Question #150075 in Physics for Muhammed

Question

The spiral spring of a spring balance is 25cm, when 5 hang on it and 30cm long when the wait is 10N. What is the length of the spring if the weight is 3N

Answer 1

$$W_1=k(x_1-x_0)\\W_2=k(x_2-x_0)\\\frac{x_2-x_0}{x_1-x_0}=\frac{W_2}{W_1} \\\frac{30-x_0}{25-x_0}=\frac{10}{5}\\x_0=20\ cm\\5=k(25-20)\\k=1\frac{N}{cm}$$

Thus,

$$3=1(x-20)\to x=23\ cm$$