To rescue a child who has fallen down a well, rescue workers fasten him. to a rope, the other endot: which is then reeled in by a machine. The child weighs 250 newtons, which means gravity pulls him: downward with 250 newtons of force. The rope pulls up the child at a steady speed. '7 n_ O The rope exerts exactly 250 newtons of force on the child after the child is- moving upward at constant speed. , Q The child's weight does not change. but gravity is less than 250 newtons of force because of the rope cancels part of the gravity. ; _ O The rope exerts more than 250 newtons of force to keep the child moving upward. _: Q The rope only need to supply less than 250 newtons of force since the child has no acceleration