an adult and a s,all child get on a seesaw that has a movable fulcrum. when the fulcrum is in the middle, the child can't tift the adult. How should the fulcrum be moved so the two can seewaw

massadult*lengthtofulcrum = mass child*lengthto fulcrum.

To determine how the fulcrum should be moved so that both the adult and small child can use the seesaw, we need to consider the principle of balanced torques. A seesaw is essentially a lever, and for it to be balanced, the torques on both sides of the fulcrum need to be equal.

In this case, the child is unable to lift the adult when the fulcrum is in the middle. This implies that the torque generated by the child's weight acting on one side of the seesaw is smaller than the torque generated by the adult's weight on the other side.

To balance the torques, we need to move the fulcrum closer to the child, effectively increasing the length of the child's side and reducing the length of the adult's side. This adjustment increases the lever arm for the child, compensating for the difference in weight and allowing the seesaw to be used by both individuals.

By moving the fulcrum closer to the child, we can achieve the desired balanced position. The exact location of the fulcrum will depend on the weights involved and their respective distances from the fulcrum. Adjustments can be made until the seesaw is in a position where both the adult and small child can enjoy using it.