when cracks form at the base of dam, the water seeping into the cracks exert a bouyant force that tends to lift the dam. As a result, the dam can topple water is seeping into the cracks at the base of a 1.8-m-thick by 4.6-m-long dam wall. The water level in the lake is 4.7 m above the cracks.

What is the buoyant force "B" exerted on the wall by the water seeping into the cracks