Question

На тело действуют три силы F1, F2 и F3. Если все силы направлены в одну сторону, равнодействующая сила равна fa=20 Н. Если силы F1 и F2 направлены в одну сторону, а F3 в противоположную, равнодействующая сила равна fb=14 Н и направлена так же, как и силы F1 и F2 . Если в одну сторону направлены силы F1 и F3 , а F2 - противоположно, равнодействующая сила fc=4 Н, и направлена так же, как и сила F2. Найти силы F1, F2 и F3. Ответ в ньютонах

Answer 1

1случай. Все сила направлены в одну сторону, тогда сила третья =2Н, 2случай. две силы3Н и 5Н направлены вправо, тогда третья сила 18Н будет направлена влево. Равнодействующая будет направлена в сторону большей силы. 3случай: 3Н вправо, 5Н влево и третья сила12Н вправо ...Можно подобрать еще варианты...

Объяснение:

Answer 2

Given Information

We have three forces acting on an object: F1, F2, and F3. The following information is provided: - When all the forces are directed in the same direction, the resultant force (fa) is 20 N. - When forces F1 and F2 are directed in the same direction, and force F3 is directed in the opposite direction, the resultant force (fb) is 14 N, and it is directed in the same direction as F1 and F2. - When forces F1 and F3 are directed in the same direction, and force F2 is directed in the opposite direction, the resultant force (fc) is 4 N, and it is directed in the same direction as F2.

Solution

To find the forces F1, F2, and F3, we can set up a system of equations based on the given information.

Let's assume that the forces F1, F2, and F3 are positive when directed to the right and negative when directed to the left.

From the given information, we can write the following equations:

1. When all forces are directed in the same direction: - F1 + F2 + F3 = 20 N

2. When forces F1 and F2 are directed in the same direction, and force F3 is directed in the opposite direction: - F1 + F2 - F3 = 14 N

3. When forces F1 and F3 are directed in the same direction, and force F2 is directed in the opposite direction: - F1 - F2 + F3 = 4 N

We can solve this system of equations to find the values of F1, F2, and F3.

Let's solve the system of equations using the substitution method:

From equation 2, we can express F3 in terms of F1 and F2: - F3 = F1 + F2 - 14

Substituting this value of F3 into equation 3, we get: - F1 - F2 + (F1 + F2 - 14) = 4

Simplifying the equation: - 2F1 - 14 = 4 - 2F1 = 18 - F1 = 9 N

Substituting the value of F1 into equation 2, we get: - 9 + F2 - (9 + F2 - 14) = 14 - 9 + F2 - 9 - F2 + 14 = 14 - 14 = 14

This equation is true, which means that the value of F2 can be any real number.

Substituting the values of F1 and F2 into equation 1, we get: - 9 + F2 + F3 = 20 - F3 = 20 - 9 - F2 - F3 = 11 - F2

So, the forces F1, F2, and F3 are: - F1 = 9 N - F2 can be any real number - F3 = 11 - F2

Therefore, the forces F1, F2, and F3 are 9 N, any real number, and 11 minus that real number, respectively.