A 30 kg girl sits on a seesaw 4.0 m from the fulcrum. what distance from the fulcrum should a 40kg boy sit in order to balance the seesaw

Answer: 3.0 m

Explanation:

Moment of force about the fulcrum is equal to balance the see saw:

mg d = m'g d'

It is given that

mass of the girl, m = 30 kg

distance from the fulcrum, d = 4.0 m

mass of the boy, m' = 40 kg

Distance from the fulcrum, d' = ?

⇒30 kg*4.0 m = 40 kg * d'

⇒d' = 120 kg. m / 40 kg = 3.0 m

Thus, in order to balance the see saw, a 40 kg boy must sit at a distance of 3.0 m from the see saw.