Question

A horizontal bar with a constant cross-section is subjected to loading as shown in the figure. The Young's moduli for the sections AB and BC are 3E and E, respectively.
For the deflection at C to be zero, the ratio P/F is

• A. 4

Answer 1

The correct option is A 4
${\Delta }_c=0$

${\Delta }_{BC}+{\Delta }_{AB}=0$

$\frac{FL}{AE}+\frac{(F-P)L}{A\times 3E}=0$

$F+\frac{F-P}{3}=0$

3F + F- P = 0

4F = P

$or\frac{P}{F}=4$