Also, you can think of it like water polo ball. If you take a water polo ball in the water, put your hand on it and press it down, you get pressure up against it that come up.

你也可以想象成一只水球，如果你拿个水球放在水中，把手放球上向下压，你就会得到上升的反作用力。

youdao

Also, you can think of it like water polo ball. If you take a water polo ball in the water, put your hand on it and press it down, you get pressure up against it that come up.

你也可以想象成一只水球，如果你拿个水球放在水中，把手放球上向下压，你就会得到上升的反作用力。

youdao