The kinetic energy (KE) of the glider can be calculated using the formula:
\[
\text{KE} = \frac{1}{2} m v^2
\]
where \( m = 0.240 \, \text{kg} \) is the mass of the glider and \( v = 0.400 \, \text{m/s} \) is its velocity.
\[
\text{KE} = \frac{1}{2} \times 0.240 \, \text{kg} \times (0.400 \, \text{m/s})^2 = 0.0192 \, \text{J}
\]
The elastic potential energy (PE) stored in the spring is given by:
\[
\text{PE} = \frac{1}{2} k x^2
\]
where \( k = 6.00 \, \text{N/m} \) is the spring constant and \( x = 0.100 \, \text{m} \) is the initial stretch of the spring.
\[
\text{PE} = \frac{1}{2} \times 6.00 \, \text{N/m} \times (0.100 \, \text{m})^2 = 0.0300 \, \text{J}
\]
The total mechanical energy (E) of the system is the sum of the kinetic energy and the elastic potential energy:
\[
E = \text{KE} + \text{PE} = 0.0192 \, \text{J} + 0.0300 \, \text{J} = 0.0492 \, \text{J}
\]
When the glider comes momentarily to rest, all the mechanical energy is converted into elastic potential energy. Thus, we set the total mechanical energy equal to the potential energy at maximum stretch:
\[
E = \frac{1}{2} k x_{\text{max}}^2
\]
Solving for \( x_{\text{max}} \):
\[
0.0492 \, \text{J} = \frac{1}{2} \times 6.00 \, \text{N/m} \times x_{\text{max}}^2
\]
\[
x_{\text{max}}^2 = \frac{0.0492 \, \text{J}}{3.00 \, \text{N/m}} = 0.0164 \, \text{m}^2
\]
\[
x_{\text{max}} = \sqrt{0.0164 \, \text{m}^2} = 0.1281 \, \text{m}
\]
- Total mechanical energy: \(\boxed{0.0492 \, \text{J}}\)
- Maximum stretch of the spring: \(\boxed{0.1281 \, \text{m}}\)