A truck with mass $500\,\text{kg}$ starts from rest at the top of a stretch of track that is $400\,\text{m}$ long and $30\,\text{m}$ high, as shown. The frictional force on the truck is $250\,\text{N}$ for the whole journey. Determine the truck's final speed.
- A$14\,\text{m s}^{-1}$
- B$24\,\text{m s}^{-1}$
- C$31\,\text{m s}^{-1}$
- D$190\,\text{m s}^{-1}$