Question

In the arrangement as shown, the spheres $A$, $C$ and block $B$ of same mass move together due to sufficient friction at their contacts with coefficient of friction $\mu$. The other surfaces are smooth and force constant of all springs is K. When the lower springs are compressed by x, what is the reaction exerted by .$A$ on $B$? The natural length of all springs is same.

• A. $\frac{2kx}{\mu }$
• B. $\frac{kx}{2\mu }$
• C. $\frac{kx}{\mu }$
• D. $\frac{2kx}{3\mu }$

Answer 1

The correct option is A $\frac{2kx}{\mu }$

Frictional force $fs=kx+kx=2kx$

$\mu N=2kxN=\frac{2kx}{\mu }$

$N=$ Reaction Force.