A 69.0-kg boy and his 42.0-kg sister, both wearing roller blades, face each other at rest. The girl pushes the boy hard, sending him backward with a velocity 2.30 m/s toward the west. Ignore friction. (a) Describe the subsequent motion of the girl. She will move west, in the same direction as her brother, with a speed 2.30 m/s. O She will move east, directly away from her brother with a speed 1.15 m/s. O She will move east, directly away from her brother with a speed 4.93 m/s. O She will move east, directly away from her brother with a speed 3.78 m/s. (b) How much potential energy in the girl's body is converted into mechanical energy of the boy-girl system? J (c) Is the momentum of the boy-girl system conserved in the pushing-apart process? O Yes O No (d) If so, explain how that is possible considering there are large forces acting. (If momentum is not conserved, enter "Momentum is not conserved.") This answer has not been graded yet. (e) If so, explain how that is possible considering there is no motion beforehand and plenty of motion afterward. (If momentum is not conserved, enter "Momentum is not conserved.")

A 69.0-kg boy and his 42.0-kg sister, both wearing roller blades, face each other at rest. The girl pushes the boy hard, sending him backward with a velocity 2.30 m/s toward the west. Ignore friction. (a) Describe the subsequent motion of the girl. She will move west, in the same direction as her brother, with a speed 2.30 m/s. O She will move east, directly away from her brother with a speed 1.15 m/s. O She will move east, directly away from her brother with a speed 4.93 m/s. O She will move east, directly away from her brother with a speed 3.78 m/s. (b) How much potential energy in the girl's body is converted into mechanical energy of the boy-girl system? J (c) Is the momentum of the boy-girl system conserved in the pushing-apart process? O Yes O No (d) If so, explain how that is possible considering there are large forces acting. (If momentum is not conserved, enter "Momentum is not conserved.") This answer has not been graded yet. (e) If so, explain how that is possible considering there is no motion beforehand and plenty of motion afterward. (If momentum is not conserved, enter "Momentum is not conserved.")