To find the magnitude of the net force on the first glider (mass \( m_1 = 350 \) kg), we can use Newton's second law of motion, which states:
\[ F_{\text{net}} = m \cdot a \]
where:
- \( F_{\text{net}} \) is the net force,
- \( m \) is the mass,
- \( a \) is the acceleration.
In this case, the acceleration \( a \) is given as \( 1.3 , \text{m/s}^2 \).
Now, substituting the known values for the first glider:
\[ F_{\text{net,1}} = m_1 \cdot a = 350 , \text{kg} \cdot 1.3 , \text{m/s}^2 \]
Calculating the force:
\[ F_{\text{net,1}} = 350 \cdot 1.3 = 455 , \text{N} \]
Thus, the magnitude of the net force on the first glider is:
\[ \boxed{455 , \text{N}} \]