試題詳解

34. A block of density 800 kg/m³ floats face down in a fluid of density 1200 kg/m³. The block has height H= 6 cm. If the block is held fully submerged and then released, what is the magnitude of its initial acceleration?
(A) 2.45 m/s²
(B)19.6 m/s²
(C)0m/s² 
(D)9.8 m/s² 
(E) 4.9 m/s²