To calculate the force needed to stretch a spring, we can use Hooke’s Law, which is given by the equation:
\[ F = k \cdot x \]
where:
- \( F \) is the force exerted by the spring (in Newtons, N),
- \( k \) is the spring constant (in Newtons per meter, N/m),
- \( x \) is the displacement of the spring from its equilibrium position (in meters, m).
Given:
- \( k = 63.4 , \text{N/m} \)
- \( x = 0.9 , \text{m} \)
Now, substituting the given values into the formula:
\[ F = 63.4 , \text{N/m} \times 0.9 , \text{m} \]
Calculating the force:
\[ F = 63.4 \times 0.9 = 57.06 , \text{N} \]
Thus, the force needed to stretch the spring is:
\[ \boxed{57.06 , \text{N}} \]