Question

Поднимая груз массой 40 кг с помощью подвижного блока, на трос действуют силой 250 Н. Каков коэффициент полезного действия блока?

Answer 1

Кпд(по формуле)=Апол/Азатр*100%
А полезная дана, это 250 Н
нам необходимо найти А затраченную
Азатр=mg=40*10=400Н
кпд=250/400*100%=62.5% или просто 0,625

Answer 2

Calculation of the Mechanical Advantage

To determine the coefficient of useful work (also known as the mechanical advantage) of the block, we need to calculate the ratio of the output force to the input force. In this case, the output force is the force exerted on the load, which is 250 N, and the input force is the force applied to the rope.

The formula for mechanical advantage is:

Mechanical Advantage = Output Force / Input Force

In this case, the output force is 250 N and the input force is unknown. Let's assume the input force is F.

Mechanical Advantage = 250 N / F

To find the mechanical advantage, we need to solve for F.

Calculation of the Input Force

To calculate the input force, we can rearrange the formula for mechanical advantage:

F = Output Force / Mechanical Advantage

Substituting the given values, we have:

F = 250 N / Mechanical Advantage

Since the mechanical advantage is unknown, we cannot calculate the exact value of the input force without additional information.

Conclusion

Without knowing the mechanical advantage of the block, we cannot determine the coefficient of useful work. To calculate the mechanical advantage, we need to know either the input force or the output force.