To calculate the force required to accelerate the skateboarder, you can use Newton's second law of motion, which states that \( F = m \cdot a \), where \( F \) is the force, \( m \) is the mass, and \( a \) is the acceleration.
Given:
- Mass (\( m \)) = 50 kg
- Acceleration (\( a \)) = 0.8 m/s²
Substituting the values into the formula:
\[ F = 50 , \text{kg} \cdot 0.8 , \text{m/s}^2 \] \[ F = 40 , \text{N} \]
The correct answer is: d) 40 N.