Who should sit farther from the center of a uniform seesaw, a 93-kg man or his 33-kg son, for the seesaw to remain in a horizontal position? Explain.

Two objects of masses m₁ and m₂ are attached to a seesaw. The seesaw is made of a bar that has length l and is pivoted so that it is free to rotate in the vertical plane without friction. Assume that the pivot is attached tot he center of the bar.

You are to find the angular acceleration of the seesaw when it is set in motion from the horizontal position. In all cases, assume that m1>m2.

Part A

Assume that the mass of the swing bar, as shown in the figure, is negligible. (Figure 1)

Find the magnitude of the angular acceleration α of the seesaw.

Express your answer in terms of some or all of the quantities m1, m2, l, as well as the acceleration due to gravity g.

Part B

In what direction will the seesaw rotate, and what will the sign of the angular acceleration be?

On a seesaw shown below, mass A is 60 kg, mass B is 30 kg, and mass C is 10 kg. Mass A is 1.0 m from the pivot. Mass C is 3.0 m from the pivot. The seesaw is at an angle of 30˚ from the horizontal. Calculate the torques of mass A and mass C about the pivot. Where should you place mass B in relation to the pivot for the system to be in rotational equilibrium?