See-saw Physics for Kids

I think I was fourteen before the physics of levers and fulcrums was presented to me at school. At the time I was puzzled that everyone didn’t know this stuff already. After all, which kid did not have extensive experience of seesaws, often shared with people of a different size?

I decided to try this out with Grace. She got all of the following questions right, first time, without assistance.

Seesaw Questions for a Ten-Year Old

Grace (50kg) and Dan (100kg) are playing on a seesaw that is 4m long. Dan is standing at 1.0m on his side. Grace is at 2m on her side. The seesaw is balanced.  (I supplied an illustration of this).

To keep the seesaw balanced:

  1. If Dan moves to 0.5m, where will Gracie have to stand?
  2. If Dan stands at 0.5m and Annie (50kg) stands on Gracie’s side at 0.5m, where will Gracie have to stand?
  3. If Annie stands with Dan at 0.5m, where will Gracie have to stand?
  4. If Dan stands at 1.0 and Annie stands on Gracie’s side at 0.5m, where will Gracie have to stand?