Question

20 баллов Человек с помощью одиночного подвижного блока поднимает некоторый груз на высоту 7м, прикладывая к свободному концу веревки силу 160Н. Найдите работу, совершаемую человеком при этом. Какую новую работу совершит человек, если он станет с помощью этого блока поднимать на ту же высоту груз, вес которого увеличен на 20Н?

Answer 1

F=P/2
A=P*h
A=2F*h
А=2*160*7=2240Дж(след. если на 20 Н больше, 160+20)

Answer 2

Problem Analysis

We are given that a person is using a single movable pulley to lift a load to a height of 7m. The person applies a force of 160N to the free end of the rope. We need to find the work done by the person in lifting the load. Additionally, we need to determine the new work done by the person if the weight of the load is increased by 20N.

Solution

To find the work done by the person in lifting the load, we can use the formula:

Work = Force × Distance

In this case, the force applied by the person is 160N and the distance over which the force is applied is 7m. Therefore, the work done by the person is:

Work = 160N × 7m

To find the new work done by the person when the weight of the load is increased by 20N, we need to calculate the new force applied by the person. The new force can be found by adding 20N to the original force of 160N. Let's call the new force F_new.

F_new = 160N + 20N

Once we have the new force, we can use the same formula as before to calculate the new work done by the person. The distance over which the force is applied remains the same at 7m.

New Work = F_new × 7m

Let's calculate the values.

Calculation

The work done by the person in lifting the load is:

Work = 160N × 7m

Using a calculator, we find:

Work = 1120 Joules

The new force applied by the person when the weight of the load is increased by 20N is:

F_new = 160N + 20N

Using a calculator, we find:

F_new = 180N

The new work done by the person in lifting the load with the increased weight is:

New Work = 180N × 7m

Using a calculator, we find:

New Work = 1260 Joules

Answer

The work done by the person in lifting the load to a height of 7m is 1120 Joules. If the person starts lifting a load with a weight increased by 20N, the new work done by the person will be 1260 Joules.

Please let me know if you need any further clarification.