Task: Complete a diagram to show where two people will sit on a seesaw to balance it, and explain answer.

Curriculum Links:

Answers/responses:

Y10 (09/1997)

a)

Sam must sit half the distance from the centre (fulcrum) than Terry does.

easy

b)

As Terry is lighter than Sam he needs to sit further away from the midpoint (or vice versa). To balance the see-saw, the distance of Terry from the fulcrum for Terry needs to be twice that of Sam. (Turning moment of Sam's force must equal the turning moment of Terry's force as shown by the equations and diagram below.)