Question

All surfaces shown in figure are smooth. System is released with the spring unstretched. In equilibrium, compression in the spring wiil be –

• A.
• B. $\frac { 2 \mathrm { mg } } { \mathrm { k } }$
• C.
• D. $\frac { \mathrm { mg } } { \mathrm { k } }$

Answer 1

Answer: (D)

$\frac { \mathrm { mg } } { \mathrm { k } }$

Answer 2

Let N be the normal reaction between m and M,

Equilibrium of M

N sin 45⁰ = kx … (i)

Equilibrium of m in vertical direction gives

N cos 45⁰ = mg … (ii)

From Eqs. (i) and (ii), we get

x =$\frac { \mathrm { mg } } { \mathrm { k } }$