Pregunta de entrevista

Entrevista de Mechanical Engineer



You're in a row boat, which is in a large tank filled with water. You have an anchor on board, which you throw overboard. Does the water level in the tank rise or fall?


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7 respuestas


Actually I feel the water level won't change. Since, the anchor is thrown from the boat there are two situations. a. Before being thrown : The anchor is in the boat and it's weight is accounted by the volume submerged. b. After being thrown: The anchor is now transferred from the boat to the tank. So even though the water level increases, the volume of the boat submerged, decreases. In essence one balances the other and there shouldn't be any change in the water level.

Vishnu en


When an object is submerged in water , the lift/buoyant force on it is equal to the weight of water displaced. Case 1 Mw1*g = (Mb +Ma)*g ; Mw = dw*(A*h1) h1 = (Mb+Ma)/(dw) Case 2 , Boat is floating and anchor is completely submerged. h2 = (Mb)/(dw) +Ma/(d_steel) , where d_steel is density of steel > density of water (dw) clearly h2 < h1 , so the water level falls

Jimmy en


Two possibilities Water displaced is proportional to buoyancy = weight supported 1. The anchor is attached to the boat and does not reach bottom Total buoyancy = boat + anchor which doesn't change before or after -> no change in water level 2. The anchor rests on the bottom of the lake Total buoyancy after water level lowered

Anónimo en


Not enough information to determine the answer. If the anchor is attached to the boat and does not rest on the bottom of the tank, the water would rise since the displacement caused by the boat wouldn't change, but you are adding the volume of the anchor..

Andrew en


By Archimedes Principle, water is displaced by Anchor's volume. Putting a new anchor down, and assuming that will not affect the boat's relative position with the water level, more water is displaced. The volume of water equals to the volume of anchor. You can even find the amount by mass of water being displaced by running volume x rho. This answer assumes no ripple effects. Assumes any the person's motion does not cause boat to move its height position at all.

Smarty en


Depends on the size and weight of the anchor.

Chris en


Water level in the tank will fall. because amount of water displaced by Anchor on board is larger than amount of water displaced by Anchor thrown overboard.

Anuj en

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