Answer:
about 0.20
Step-by-step explanation:
The speed, acceleration, and distance satisfy the equation ...
v² = 2ad
So the acceleration is ...
a = v²/(2d) = (6 m/s)²/(2×9 m) = 2 m/s²
If we take the acceleration due to gravity to be 9.8 m/s², the coefficient of kinetic friction is the ratio of these:
k = (2 m/s²)/(9.8 m/s²) ≈ 0.20