To calculate the force needed to accelerate an object, you can use Newton's second law of motion, which states:
\[ F = m \cdot a \]
where:
- \( F \) is the force in newtons (N),
- \( m \) is the mass in kilograms (kg),
- \( a \) is the acceleration in meters per second squared (m/s²).
In this case, the mass \( m \) of the skier is 60 kg and the acceleration \( a \) is 3 m/s². Plugging in these values:
\[ F = 60 , \text{kg} \cdot 3 , \text{m/s}² \]
\[ F = 180 , \text{N} \]
Therefore, a force of 180 newtons is needed to accelerate the 60 kg skier at 3 m/s².