- #1

Wasseem92

- 4

- 0

well i tried solving this question and my teacher gave this as a solution:

The center of gravity of the see-saw is assumed to be in the center, assuming that it is uniform. The force diagram is therefore as shown below. mss = 30 kg is the mass of the see-saw, mc = 20 kg is the mass of the child, and L is the length of the see-saw.

Figure 8.3: Problem 8.1

In order to find the distance x from the child to the fulcrum we can do a torque balance about the fulcrum:

sum of torque = (L/6)mssg - xmcg = 0

so that

x = (L*mss)/(6*mc) = = (1/4) L.

My question is: why did he start of with a distance of (L/6). Please i need help, this really baffles me.

Thank you.