Question

Люди добрые помогите! Непонятная задача по физике №22.2 учебник Кабардина 7 класс Докажите, что при подъеме груза с помощью рычага, при отсутствии силы трения КПД = 1

Answer 1

F2=сила тяжести груза
F1=сила,которую прикладывают к веревке,что-бы поднять груз.
H2=высота,на которую нужно поднять груз (путь, который груз пройдет при его поднятии
H1=высота,на которую  пришлось вытянуть веревку.

Answer 2

Understanding the Problem

You are asking for help with problem 22.2 from the physics textbook "Kabardina" for 7th grade. The problem asks you to prove that the efficiency (КПД) is equal to 1 when lifting a load using a lever in the absence of friction.

Solution

To prove that the efficiency is equal to 1 when lifting a load using a lever without friction, we need to understand the concept of efficiency and how it is calculated.

Efficiency (КПД) is a measure of how effectively a machine or system converts input energy into useful output energy. It is calculated by dividing the useful output energy by the total input energy and multiplying by 100 to express it as a percentage.

In this case, when lifting a load using a lever without friction, the input energy is the work done on the lever, and the output energy is the work done on the load. Since there is no friction, all the input energy is converted into useful output energy.

Therefore, the efficiency (КПД) is equal to 1 or 100% because all the input energy is converted into useful output energy.

I hope this explanation helps you understand the problem. If you have any further questions, please feel free to ask!

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