Question

A steel strip of length L= 200 mm is fixed at A and rest B on a vertical spring of stiffness k = 2N/mm. The steel strip is 5 mm wide and 10 mm thick.A vertical load P=50 N is applied at B as shown. Consider E=200 GPa, the force (in N) developed in the spring is

• A. 3

Answer 1

The correct option is A 3

${\Delta }_B=\frac{(P-R)L^3}{3EI}=\frac{R}{K}...\left(1\right)$

where R-reaction/ force in the spring
$\Rightarrow \frac{(50-R){200}^3}{3\times 200\times {10}^3\times \frac{5\times {10}^3}{12}}=\frac{R}{2}$

$0.064(50-R)=R$

$3.2=R+0.064R$

$R=3.00N$