"A spring of natural length 1.5cm is extended by 0.02cm by a force of 1.5N.what will the length be when the applied force is 4.0N"

1 answer

To determine the length of the spring when a force of 4.0 N is applied, we can use Hooke's Law, which states that the extension of a spring is directly proportional to the force applied to it, within the elastic limit of the material. Hooke's Law can be expressed as:

\[ F = k \cdot x \]

where:

  • \( F \) is the force applied,
  • \( k \) is the spring constant,
  • \( x \) is the extension of the spring from its natural length.
  1. First, we need to calculate the spring constant \( k \) using the initial force and extension:

    Given:

    • Natural length of the spring = 1.5 cm
    • Extension at 1.5N = 0.02 cm

    Extension in meters: \[ x_1 = 0.02 , \text{cm} = 0.0002 , \text{m} \]

    Using Hooke's Law: \[ F_1 = k \cdot x_1 \] \[ 1.5 = k \cdot 0.0002 \]

    Solving for \( k \): \[ k = \frac{1.5}{0.0002} = 7500 , \text{N/m} \]

  2. Now, we can find the extension when a force of 4.0 N is applied:

    Given:

    • \( F_2 = 4.0 , \text{N} \)

    Using Hooke's Law again: \[ F_2 = k \cdot x_2 \] \[ 4.0 = 7500 \cdot x_2 \]

    Solving for \( x_2 \): \[ x_2 = \frac{4.0}{7500} = 0.00053333 , \text{m} \] \[ x_2 \approx 0.0533 , \text{cm} \]

  3. Finally, we can find the new length of the spring when the force of 4.0 N is applied:

    New length \( L \) is the natural length plus the extension: \[ L = 1.5 , \text{cm} + 0.0533 , \text{cm} \] \[ L \approx 1.5533 , \text{cm} \]

So the length of the spring when a force of 4.0 N is applied will be approximately 1.553 cm.