John and Barry are pulling on a fence post with ropes while their friend Pat uses a chain-saw to sheer it at ground-level. John applies a force of 75.0N [40*] on one rope while Barry applies a force of 85.0N [340*] on the other rope. What is the net force on the post? Show your work.

Answer 1

Fn = 75N[40o] + 85N[340o]

X = 75*cos40 + 85*cos340 = 137.3 N.
Y = 75*sin40 + 85*sin340 = 19.14 N.

tan A = Y/X = 19.14/137.3 = 0.13940
A = 7.94o

Fn=X/cosA = 137.3/cos7.94=138.6 N[7.94o]

Answer 2

net force = 139N [7.93 degrees]