To calculate the mass that would support the force of 400 newtons when cables are installed in the trunking, we can use the formula:

Mass = Force / Acceleration due to gravity

First, we need to convert the force from newtons (N) to kilograms (kg) by dividing it by the acceleration due to gravity (g), which is approximately 9.8 m/s².

1 kilogram (kg) = 1 newton (N) / 9.8 m/s²

Mass = 400 N / 9.8 m/s²

Mass ≈ 41.02 kg

Therefore, the mass that would support the force of 400 newtons when cables are installed in the trunking is approximately 41.02 kilograms.