The maximum instantaneous extension, produced by an unknown falling weight through a height of 4cm in a vertical bar of length 3m and of cross section area 5cm². What will be the instantaneous stress induced in the vertical bar and the value of unknown weight if E = 200GPa?

• A. 1700 N
• B. 1459.4 N
• C. 1745.8 N
• D. 1947.5 N