Question

Из пластилина слепили тело в форме куба и положили его на горизонтальную поверхность стола. При этом давление тела на стол составило 108 Па. Затем на тело положили стальной куб, ребро которого в два раза больше ребра пластилинового куба. Пластилин расплющился, и площадь его контакта со столом увеличилась втрое. Чему стало равным давление пластилина на стол? Ответ выразить в ПаПа, округлив до целых. Плотность пластилина составляет 1200 кг/м3, а стали – 7800 кг/м3.

Answer 1

Зачем учиться если можно заниматься ерундой?

Answer 2

Calculation of Pressure

To calculate the pressure exerted by the clay and steel cubes on the table, we need to use the formula:

Pressure (P) = Force (F) / Area (A)

The force exerted by an object is equal to its weight, which can be calculated using the formula:

Force (F) = Mass (m) x Acceleration due to gravity (g)

The area of contact between the object and the table is given as a factor in the problem.

Let's calculate the pressure exerted by the clay cube and the steel cube separately.

Calculation for the Clay Cube

Given: - Density of clay = 1200 kg/m^3 - Side length of the clay cube = x (unknown) - Pressure exerted by the clay cube on the table = 108 Pa

To find the side length of the clay cube, we need to calculate its mass first.

The volume of the clay cube can be calculated using the formula:

Volume (V) = Side length (x)^3

The mass of the clay cube can be calculated using the formula:

Mass (m) = Density (ρ) x Volume (V)

Substituting the values, we have:

Mass (m) = 1200 kg/m^3 x (x^3)

The force exerted by the clay cube can be calculated using the formula:

Force (F) = Mass (m) x Acceleration due to gravity (g)

Substituting the values, we have:

Force (F) = (1200 kg/m^3 x (x^3)) x 9.8 m/s^2

Now, we can calculate the area of contact between the clay cube and the table.

Given that the area of contact increases three times when the clay cube is flattened, we can say:

Area of contact (A) = 3 x (x^2)

Finally, we can calculate the pressure exerted by the clay cube on the table using the formula:

Pressure (P) = Force (F) / Area (A)

Substituting the values, we have:

108 Pa = [(1200 kg/m^3 x (x^3)) x 9.8 m/s^2] / [3 x (x^2)]

Now, let's solve this equation to find the value of x.

Calculation for the Steel Cube

Given: - Density of steel = 7800 kg/m^3 - Side length of the steel cube = 2x (twice the side length of the clay cube) - Area of contact with the table increased three times

Using similar calculations as above, we can calculate the pressure exerted by the steel cube on the table.

Answer

To find the pressure exerted by the clay cube on the table, we need to solve the equation:

108 Pa = [(1200 kg/m^3 x (x^3)) x 9.8 m/s^2] / [3 x (x^2)]

Unfortunately, we cannot solve this equation without knowing the value of x. The problem does not provide enough information to determine the exact value of x.

Therefore, we cannot determine the final pressure exerted by the clay cube on the table.