The truss is made of three A-36 steel members, each having a cross-sectional area of 400 mm^2.
A triangular three-member frame A B C. Horizontal member A C of length 1.4 meters is pin-supported at A and roller-supported at C. Pin B is 0.8 meters right and 0.8 meters up from A, with P downward and 5 kilo Newtons rightward on B.
Determine the magnitude P required to displace the roller to the right 0.25 mm. Express your answer to three significant figures and include appropriate units.