6. A 12 N object is attached vertically by a string to a frictionless car that runs along a level track. The car with mass m kg covers a distance of 1.25 m in 5.0 s after it starts from rest. Find the gain in kinetic energy of the car and the hanging object A. 15 J B. 30 J C. 45 J D. 60 J please show complete solution

6. A 12 N object is attached vertically by a string to a frictionless car that runs along a level track. The car with mass m kg covers a distance of 1.25 m in 5.0 s after it starts from rest. Find the gain in kinetic energy of the car and the hanging object A. 15 J B. 30 J C. 45 J D. 60 J please show complete solution