As shown in the figure, F1, F2, F3 and F4 are four common point forces on the same horizontal plane. Their sizes are F1 = 1n, F2 = 2n, F3 = 3N, F4 = 4N respectively. The included angles between them are 60 °, 90 ° and 150 ° respectively. If the direction of F1 is positive, their resultant force is small___ N. Direction__________ .

As shown in the figure, F1, F2, F3 and F4 are four common point forces on the same horizontal plane. Their sizes are F1 = 1n, F2 = 2n, F3 = 3N, F4 = 4N respectively. The included angles between them are 60 °, 90 ° and 150 ° respectively. If the direction of F1 is positive, their resultant force is small___ N. Direction__________ .

Size: 1n, direction: between F2 and F3, with an angle of 60 ° with F2 and 30 ° with F3

If a force F = 10N is decomposed into two forces F1 and F2, and the direction of F1 is known to be at an angle of 30 degrees with F, then the size of F2 may be
A.2N
B.3N
C.4N
D.10N

As shown in the picture
The size of F2 can range from & nbsp; & nbsp; 5N to + ∞
When F2 is the smallest, it is 5N (30 degrees, bevel 10 / 2 = 5)
Therefore, choose D