Question

The boy gets off the see-saw and a bigger boy gets on it in the same place. The girl stays in the position shown in Figure 3. The plank is balanced. The weight of the plank is 270N. Calculate the weight of the bigger boy.

Answer 1

To calculate the weight of the bigger boy on the see-saw, we can use the principle of torque equilibrium. By setting up an equation using the torques on both sides and plugging in the given values, we can solve for the mass of the bigger boy, which can be converted to weight.

Step-by-step explanation:

To calculate the weight of the bigger boy, we can use the principle of torque equilibrium. The torque on a see-saw is given by the product of the force and the distance from the fulcrum. Since the see-saw is balanced, the torques on both sides are equal. We can set up the equation:

(Force of smaller boy)(Distance from fulcrum) = (Force of bigger boy)(Distance from fulcrum)

Plugging in the values:

(40 kg)(3.0 m) = (mass of bigger boy)(3.0 m)

Solving for the mass of the bigger boy, we get:

mass of bigger boy = (40 kg)(3.0 m) / (3.0 m) = 40 kg

Therefore, the weight of the bigger boy is 40 kg.