Answer:
58 lb
Step-by-step explanation:
We can draw a vector triangle with the 100 lb force vector starting at the tip of the 80 lb vector. Then the resultant force vector C will be the third side of the
triangle, and the angle opposite this third side will be 180 - 60 = 120 degrees.
Then using the Cosine rule
C^2 = 80^2 + 100^2 - 2*80*100*cos(120)
= 3373. 1045
C^2 = 3373.1045
C = 58 lb
The resultant force = 58 lb
