Question

36. Груз массой 400 г поднимают с помощью наклонной плоскости с КПД 80% на высоту 5 м. Длина наклонной плоскости равна 20 м. Определите силу, которую необходимо приложить к грузу. A. 8 Н В. 0,8 Н С. 1,25 н D. 20 H Е. нет правильного ответа с дано и решением ​

Answer 1

Ответ: С. 1,25 н

Объяснение:

Дано:

m=400г=0,4кг

g=10Н/кг

h=5м

L=20м

-----------------

F-?

η=Ап/Аз, где:

Ап-полезная работа;

Аз-затраченная работа

Ап=mgh, где:

m-масса  груза;

g-ускорение свободного падения;

h-высота подъема груза

Аз=F*L, где:

F-приложенная сила;

L-длина наклонной плоскости.

Отсюда:

F=mgh/(Lη)=0,4*10*5/(20*0,8)=1,25Н

Answer 2

Problem Analysis

We are given the following information: - Mass of the load: 400 g - Efficiency of the inclined plane: 80% - Height of the inclined plane: 5 m - Length of the inclined plane: 20 m

We need to determine the force required to lift the load.

Solution

To solve this problem, we can use the concept of work and energy. The work done in lifting the load is equal to the change in potential energy of the load.

The formula for work is given by:

Work = Force x Distance

The formula for potential energy is given by:

Potential Energy = Mass x Gravity x Height

Since the efficiency of the inclined plane is given as 80%, we can assume that 80% of the work done is used to lift the load, and the remaining 20% is lost due to friction and other factors.

Let's calculate the force required to lift the load.

Calculation

First, let's convert the mass of the load from grams to kilograms:

Mass = 400 g = 0.4 kg

Next, let's calculate the potential energy of the load:

Potential Energy = Mass x Gravity x Height

Using the value of gravity as 9.8 m/s^2:

Potential Energy = 0.4 kg x 9.8 m/s^2 x 5 m = 19.6 J

Since the efficiency of the inclined plane is given as 80%, we can calculate the work done as:

Work Done = Potential Energy / Efficiency

Work Done = 19.6 J / 0.8 = 24.5 J

Finally, let's calculate the force required to lift the load:

Force = Work Done / Distance

Force = 24.5 J / 20 m = 1.225 N

Therefore, the force required to lift the load is approximately 1.225 N.

Answer

The force that needs to be applied to the load is approximately 1.225 N.