Question

Лодка неподвижна в стоячей воде. Находящийся в лодке человек хочет определить ее массу. Сможет ли он это сделать, если собственная масса ему известна, но ничем ,кроме длинной веревки, он не располагает С обьеснением плиз, по возможности с формулами

Answer 1

Можно попробовать следующий способ:.
1) Сложить веревку на краю берега, предварительно привязав ее к шесту.
2) Поставить лодку перпендикулярно берега, носом к берегу.
3) В начальный момент человек должен быть на корме.
4) Перейти с кормы на нос, замечая сколько веревки освободится в результате отхода лодки( пусть L)
5) Запишем равенство модулей сил( знак опускаем) по 3 закону Ньютона: m1*a1=m2*a2. Учтем, что a=2*S/t^2. Получим m1*L=m2*l l( длина лодки)
6) L/l=m2/m1 Осталось выяснить отношение длины веревки к длине лодки, и мы узнаем массу лодки.

Answer 2

Can a person determine the mass of a stationary boat in still water if they only have their own mass and a long rope?

Yes, a person can determine the mass of a stationary boat in still water if they have their own mass and a long rope. To understand how, let's break it down step by step.

1. Principle of Buoyancy: When an object is submerged in a fluid (in this case, water), it experiences an upward force called buoyancy. This force is equal to the weight of the fluid displaced by the object.

2. Archimedes' Principle: Archimedes' principle states that the buoyant force acting on an object is equal to the weight of the fluid displaced by the object. Mathematically, it can be expressed as:

Buoyant force = Weight of the fluid displaced

3. Determining the Mass of the Boat: To determine the mass of the boat, the person in the boat can use the following steps:

a. Attach the long rope to the boat. b. Measure the length of the rope that is submerged in the water. c. Tie a known weight (which represents the person's own mass) to the other end of the rope. d. Slowly lower the weight into the water until it is fully submerged. e. Measure the length of the rope that is now submerged in the water. f. The difference in the lengths of the submerged rope before and after adding the weight represents the length of the rope that was displaced by the weight.

4. Calculating the Mass of the Boat: Using Archimedes' principle, the person can calculate the mass of the boat by equating the weight of the fluid displaced by the boat (represented by the length of the submerged rope) to the weight of the boat itself. Mathematically, it can be expressed as:

Weight of the boat = Weight of the fluid displaced

Since weight is equal to mass multiplied by the acceleration due to gravity, the equation can be rewritten as:

Mass of the boat = (Weight of the fluid displaced) / (Acceleration due to gravity)

The person can substitute the length of the submerged rope (which represents the weight of the fluid displaced) and the known value of the acceleration due to gravity to calculate the mass of the boat.

Please note that this method assumes that the boat is fully submerged in the water and that the water is still. Additionally, it is important to ensure accurate measurements and consider any other factors that may affect the calculation.

I hope this explanation helps! Let me know if you have any further questions.