A 40lb child sits at one end of a teeter-totter-totter which is 12 feet long and has the fulcrum in the center. How many feet from the fulcrum should a 60 lb child sit so the teeter-totter will balance?
To determine where the 60 lb child should sit on the teeter-totter to balance it, we need to consider the weight and distance from the fulcrum for both children.
Let's define the following variables:
- W1 = weight of the 40 lb child
- W2 = weight of the 60 lb child
- D1 = distance of the 40 lb child from the fulcrum
- D2 = distance of the 60 lb child from the fulcrum
Since the teeter-totter is in balance, the total torque on both sides of the fulcrum should be equal. Torque is calculated by multiplying the weight by the distance from the fulcrum.
So, we have the following equation for torque balance:
W1 * D1 = W2 * D2
Given that W1 = 40 lbs and W2 = 60 lbs, we need to solve for D2.
D2 = (W1 * D1) / W2
Now, we can substitute the known values into the equation and solve for D2:
D2 = (40 lbs * 12 ft) / 60 lbs
D2 = 8 ft
Therefore, the 60 lb child should sit 8 feet from the fulcrum so that the teeter-totter will balance.