A boy of mass 40kg sits at a point of 2.0m from the pivot of a see saw .Find the weight of a girl who can balance the see saw by sitting at a distance of 3.2m from the pivot(g=10N/Kg)
balance the w1 d1 = w2 d2
40g*2 = w2*3.2
the solution
To find the weight of the girl who can balance the seesaw, we need to consider the principle of moments. The principle of moments states that the sum of the clockwise moments about a pivot is equal to the sum of the anticlockwise moments about the same pivot.
In this scenario, we can set up the equation as follows:
Clockwise moment = Anticlockwise moment
The clockwise moment is given by the product of the weight and the distance from the pivot to the boy:
Clockwise moment = Weight of the boy * Distance of the boy from the pivot
The anticlockwise moment is given by the product of the weight of the girl and the distance from the pivot to the girl:
Anticlockwise moment = Weight of the girl * Distance of the girl from the pivot
In this case, the boy has a mass of 40 kg, so his weight is:
Weight of the boy = Mass of the boy * Acceleration due to gravity
= 40 kg * 10 N/kg
= 400 N
The distance of the boy from the pivot is 2.0 m.
Now, we need to find the weight of the girl, so we can rewrite the equation as:
Weight of the boy * Distance of the boy from the pivot = Weight of the girl * Distance of the girl from the pivot
Substituting the given values:
400 N * 2.0 m = Weight of the girl * 3.2 m
Simplifying the equation:
800 N*m = Weight of the girl * 3.2 m
To find the weight of the girl, we can rearrange the equation:
Weight of the girl = (800 N*m) / 3.2 m
Weight of the girl = 250 N
Therefore, the weight of the girl who can balance the seesaw by sitting at a distance of 3.2 m from the pivot is 250 N.