Ah 1:59, not so fast. Usually the angle between the two given forces A and B is often specified. As you do in the problem at 4:18. Why does every textbook and statics teacher get "tangled up" figuring out the angle. 10th grade geometry tells us that the internal angles of a parallelogram = 360 and the opposite angles are identical. Thus 2(angle 1) + 2(angle 2) = 360. Go back to 3:47, the angle between the two forces = 45 + 20 = 65. Thus: 2(65) + 2(angle opp the resultant) = 360. The angle opposite resultant = 115° Now you can apply the law of Cosines to calculate the Resultant value. Seriously, how easy is that?
Very nice video! Vector addition/subtraction is not only useful in engineering statics, but also when programming geometry/graphics :)
man your enthusiasm to teach is dope, if only you also taught electricity and magnetism.
Ah 1:59, not so fast. Usually the angle between the two given forces A and B is often specified. As you do in the problem at 4:18.
Why does every textbook and statics teacher get "tangled up" figuring out the angle.
10th grade geometry tells us that the internal angles of a parallelogram = 360 and the opposite angles are identical. Thus 2(angle 1) + 2(angle 2) = 360.
Go back to 3:47, the angle between the two forces = 45 + 20 = 65. Thus: 2(65) + 2(angle opp the resultant) = 360. The angle opposite resultant = 115°
Now you can apply the law of Cosines to calculate the Resultant value. Seriously, how easy is that?
Chuga chuga structurefree……