Question

Two block $A$ and $B$ are connected to each other as shown is fig. and spring and pulley. The block $B$ slides at a horizontal top surface of stationary block $C$ , and block $A$ slides along vertical slides of $C$ , both with same uniform speed. The coefficient of friction between the block is $0.2\left(l\right)$ , spring constant of spring is $1960N/m$ . If mass of block is $2kg$ . Find energy stored in spring,

Answer 1

For equilibrium of B, it is given as,

$\mu M_{B}g=T$

$\mu M_{B}g=kx$

$\mu M_{B}g=M_{A}g$

$M_B=\frac{M_A}{\mu }$

$M_B=\frac{2}{0.2}$

$M_B=10kg$

For equilibrium of A, it is given as,

$M_{A}g=kx$

$2\times 9.8=1960\times x$

$x=0.01m$

The energy stored in spring is given as,

$U=\frac{1}{2}k{x}^2$

$U=\frac{1}{2}\times 1960\times {\left(0.01\right)}^2$

$U=0.098J$