5. A 4768-kg roller coaster train full of riders approaches the loading dock at a speed of 17.1 m/s. It is abruptly decelerated to a speed of 2.2 m/s over a distance of 13.6 m. Determine the retarding force that acts upon the roller coaster cars. KEi PEi + Wext KEf PEf 6. A catcher's mitt recoils a distance of 12.9 cm in bringing a 142-gram baseball to a stop. If the applied force is 588 N, then what was the speed of the baseball at the moment of contact with the catcher's mitt? KEi + PEi + Wext KEf + PEf 7. An unknown force is applied to a 12 kg mass. The force acts at an angle of 30 degrees above the horizontal. Determine the force acting if the force acts for a horizontal displacement of 22 meters and increases the 12 kg mass's speed from 11 m/s to 26 m/s. Wext KEf + PEf KEi PEi + A physics teacher exerts a force upon a 3.29-kg pile of snow to both lift it and set it into motion. The 8. snow leaves the shovel with a speed of 2.94 m/s at a height of 0.562 m. Determine the work done upon the pile of snow. KEi + PEi + KEf + PEf Wext A 250.-gram cart starts from rest and rolls down an inclined plane from a height of 0.541 m. 9. Determine its speed at a height of 0.127 m above the bottom of the incline. PEf + Wext = KEf + KEi + PEi 10. A 4357-kg roller coaster car starts from rest at the top of a 36.5-m high track. Determine the speed of the car at the top of a loop that is 10.8 m high. + PEf Wnc = KEf + KEi + PEi