An object is affected by a common point F1. F2. F3. It is known that F1 = 6N, F2 = 7n, F3

An object is affected by a common point F1. F2. F3. It is known that F1 = 6N, F2 = 7n, F3

Now the resultant force of 1, F2 and F3 is zero, which means that the resultant force of F1 and F3 and F2 are equal in size and opposite in direction, right? Now F2 suddenly decreases to 16N, but F1 and F3 remain unchanged, that is, the resultant force of F1 and F3 is still 20n, and the direction is opposite to F2. Now the resultant force of the object is the resultant force of F1 and F3 (20n) - F2 (16N) = 4N, and the direction is opposite to F2
2. The method is to take the east-west direction as the x-axis and the north-south direction as the y-axis, and decompose all the forces on the XY axis (in other words, the forces are regarded as the hypotenuse of the right triangle, and the decomposed forces are the two right angles). After the decomposition, the forces on the two axes are subtracted in the opposite direction and added in the same direction, and then the forces on the two axes are regarded as the two right angles of the right triangle, Then the resultant force is the hypotenuse composed of two right angle sides. Attention is vector, so the angle (direction) also needs to be answered. The answer to this question is that the resultant force is 50N, and the direction is 37 ° East by south

The results show that the resultant forces of the three forces acting on a plane are 5N, 7n and 9N respectively______ N．

When the direction of the three forces is the same, the resultant force is the largest, f = 5 + 7 + 9N = 21n. The resultant force of 5N and 7n is greater than or equal to 2n, less than or equal to 12n, and 9N is within the range of the resultant force, so the resultant force of the three forces can be zero. Then the minimum value of the resultant force is 0. The range of resultant force is 0 ~ 21n

How to synthesize 5N and 7n forces into 9N forces? Can they be synthesized?
The book says that the resultant force of 5N and 7n ranges from 2n to 12n. Shouldn't it be 2n or 12n?

According to the composition of the forces, a closed triangle can be formed. The angle between the forces can be calculated by Pythagorean theorem