An object of density P_a, volume V_a, and weight W_a is thrown from a rowboat floating on the surface of a small pond and sinks to the bottom. The weight of the rowboat without the jettisoned object is W_b. Before the object was thrown out, the depth of the pond was h_p1, and the bottom of the boat was a distance h_b1 above the pond bottom. After the object sinks, the values of these quantities are h_p2 and h_b2. The area of the pond is A_p; that of the boat is A_b. A_b may be assumed constant, so that the volume of water displaced by the boat is A_b(h_p - h_b).
1) Derive an expression for the change in pond depth (h_p2 - h_p1) and tell if the liquid level of the pond will rise, fall, or indeterminate?