To calculate the weight of a 40-kilogram student on Earth in newtons (N), we use the formula:

Weight (F) = mass (m) × gravitational acceleration (g)

Given:

- mass (m) = 40 kilograms (kg)

- gravitational acceleration on Earth (g) = approximately 9.8 meters per second squared (m/s²)

F = 40 kg × 9.8 m/s²

F = 392 N

Therefore, a 40-kilogram student weighs approximately 392 newtons on Earth.