A box with mass $4.0\,\text{kg}$ is dragged in a straight line across a horizontal floor by a constant force $F$. The box experiences a constant frictional force of $2.0\,\text{N}$. Its speed rises from $0.50\,\text{m s}^{-1}$ to $2.5\,\text{m s}^{-1}$ over $2.0\,\text{s}$. What is the value of $F$?
- A$2.0\,\text{N}$
- B$4.0\,\text{N}$
- C$6.0\,\text{N}$
- D$7.0\,\text{N}$