Every one who can answer these 3 questions, help me to understand Physics better.It also help other people who are interested in physics. 1-Imagine you want to drink a glass of water with a straw.Where is better to put the tube for drinking water better? 2-Boats which have engine lurch and the front part of them up when they want to move.It is a logical thing but why are they lurching after some minutes that boat move with permanent speed? 3-If we place a stone on mud, it will sink at certain rate because of its weight. However if we drop the same stone from some unknown height it will sink down twice as fast. What is that height? I think the second question related to mechanic but my information is so limited, I search in internet and relevant books but i can't solve them. Please help me.