Question

Answer the question:
Different weights are hung from a spring. The diagram shows the original length of the spring, and the lengths when different weights are added.
The extension of the spring is directly proportional to the weight hung from it.
What is the weight of W ?

Answer 1

Correct option is C. 40 N
As we know that extension of the spring is directly proportional to the weight hung from it.

$$W \propto x$$

$$W_1\propto x_1$$ and $$W_2\propto x_2$$

$$\dfrac{W_1}{W_2}=\dfrac{x_1}{x_2}$$

$$\dfrac{20}{W_2}=\dfrac{25-15}{35-15}$$

$$\dfrac{20}{W}=\dfrac{25-15}{35-15}$$

$$W=40\,N$$

What is the weight of W is 40 N.