解决图片中的这道题---**Question:** 25. (8分) **Question Stem:** 如图所示，足够高的薄壁圆柱形容器的底面积是200cm²，装有深度为20cm的水。现将高为10cm、底面积为80cm²的圆柱体A轻轻放入水中 (假设物体A在液体中始终保持竖直)，待静止后A漂浮在水中，此时物体A有9cm浸在水面下；再向容器中加油 (假设油漂浮在水面上且油、水不会混溶)，直到A刚好浸没。已知：水的密度为1g/cm³，油的密度为0.8g/cm³。求： **Sub-questions:** (1) A漂浮在水中时，A物体的底部受到水的压强。 (2) A物体的密度。 (3) 从加油开始到物体A刚好浸没的过程中，物体A克服自身A重力做的功。 **Given Information:** * Container base area: 200cm² * Initial water depth: 20cm * Object A height: 10cm * Object A base area: 80cm² * Object A floats in water, 9cm submerged. * Oil is added until A is just submerged. * Oil floats on water and does not mix with water. * Density of water: 1g/cm³ * Density of oil: 0.8g/cm³ **Diagram Description:** * **Type:** Schematic diagram illustrating a container holding liquid with an object floating in it. * **Container:** Represented by vertical lines forming the sides of a container, with a horizontal line indicating the initial liquid surface level inside. * **Object:** Labeled "A", depicted as a rectangle, positioned inside the container and floating in the liquid. The lower part of the object is submerged. Lines extending horizontally from the sides of object A to the container walls might indicate the water level or support, but more likely represent the water surface. * **Liquid:** Represented by the region below the water surface line, inside the container. The diagram shows object A floating in this liquid. * **Labels:** The object is labeled "A". * **Relative Position:** Object A is inside the container, floating with a portion below the liquid surface and a portion above. The liquid surface is shown.