Question

Линейка массой 30г и длинной 20см лежит на поверхности стола . Её взяли за один конец и поставили вертикально. Насколько изменилась потенциальная энергия линейки ? Напишите полное решение

Answer 1

отметь пожалуйста как лучшее решение :)) изменение Е(п)=m*g*h, т.к. h=l/2, то
изменение Е(п)=m*g*l/2=0,03*10*0,2/2=0,03 (Дж)

Answer 2

Problem Analysis

We are given a ruler with a mass of 30g and a length of 20cm. The ruler is initially lying on a table. We then lift one end of the ruler and place it vertically. We need to determine how much the potential energy of the ruler changes in this process.

Solution

The potential energy of an object is given by the equation:

Potential Energy (PE) = mass (m) * gravitational acceleration (g) * height (h)

In this case, the ruler is initially lying on the table, so its height is zero. When we lift one end of the ruler and place it vertically, the height of the ruler changes to its full length, which is 20cm.

Let's calculate the change in potential energy step by step:

1. Convert the length of the ruler from centimeters to meters: - 20cm = 0.2m

2. Calculate the change in potential energy: - Change in Potential Energy (ΔPE) = m * g * h - ΔPE = 0.03kg * 9.8m/s^2 * 0.2m - ΔPE = 0.0588 Joules

Therefore, the potential energy of the ruler increases by approximately 0.0588 Joules when we lift one end and place it vertically.

Conclusion

The potential energy of the ruler increases by approximately 0.0588 Joules when we lift one end and place it vertically.

Note: The above solution assumes that the ruler is lifted vertically without any additional forces acting on it.