Question

The cross-section of a built-up wooden beam as shown in the figure (not drawn to scale) is subjected to a vertical shear force of 8kN. The beam is symmetrical about the neutral axis (N.A.) shown, and the moment of inertia about N.A. is $1.5\times {10}^{9}m{m}^4$. Considering that the nails at the location P are speced longitudinally (along the length of the beam) at 60 mm, each of the nails at P will be subjected to the shear force of

• A. 60 N
• B. 120 N
• C. 240 N
• D. 480 N

Answer 1

The correct option is C 240 N

Shear force in nail at $P=\frac{VA\overline{y}}{I}\times \text{pitch}$
$=\frac{8000\times 100\times 50\times 150Nm{m}^3}{1.5\times {10}^4}\times 60mm$
$=240/N$
So shear force in nail = 240 N