A seesaw consist of uniform bar 4m long and of mass 5kg. A boy of weight 42N at end A of the seesaw while another weight of 38N sits at the end B. At what point must the seesaw be pivoted if is to be balanced (take acceleration due to gravity= 10m/s^2)

The seesaw can be balanced when the moments on both sides of the pivot point are equal. The moment is calculated as the force multiplied by the distance from the pivot point. In this case, the boy at end A has a moment of 42N * 4m and the weight at end B has a moment of 38N * 4m. To find the pivot point, we need to divide the distance from the weight at end A by the distance from the weight at end B.

So, 4m/(4m-x)=42N/38N

Solving for x: x=0.36m

So, the seesaw must be pivoted 0.36m from the end B.