Question

A block P of mass m is placed on smooth horizontal surface and connected with a spring. Another block Q of same mass is placed on the block P. The two blocks are pulled by a distance A and released. The blocks oscillates without slipping on each other. Then match the matrix.

$\begin{array}{cc}\text{(A) Friction force on the block Q when both the}& \text{(P) towards right}\\ \text{blocks coming towards equilibrium position from left is}& \\ \text{(B) Friction force on the block Q when both blocks are going}& \text{(Q) towards left}\\ \text{right from equilibrium position is(exclude the equilibrium position)}& \\ \text{(C) Friction force will be maximum on Q}& \text{(R) at the equilibrium position}\\ \text{(D) Friction force on P when both blocks are coming towards}& \text{(S) at the extreme position}\\ \text{the equilibrium position from right is}& \\ & \text{(T) none of these}\end{array}$

• A. A-P; B-Q; C-S; D-P
• B. A-Q; B-P; C-S; D-T
• C. A-P; B-Q; C-R; D-T
• D. A-T; B-Q; C-S; D-R

Answer 1

The correct option is A A-P; B-Q; C-S; D-P

Friction provides necessary restoring force to block Q. It is always directed towards mean position. Its value is maximum at extreme position because in SHM, the restoring force is proportional to distance from the mean position.