FrictionMedium
Question
Two blocks of masses m1 and m2 are connected with a massless unstretched spring and placed over a plank moving with an acceleration ′a′ as shown in figure. The coefficient of friction between the blocks and platform is μ.


Options
A.spring will be stretched if a > μg
B.spring will be compressed if a ≤ μg
C.spring will neither be compressed nor be stretched only if a ≤ μg
D.spring will be in its natural length under all conditions only if initial velocities of blocks are same
Solution
(D) Let the value of ′a′ be increased from zero. As long as a ≤ μg, there shall be no relative motion between m1 or m2 and platform, that is, m1 and m2 shall move with acceleration a.
As a > mg the acceleration of m1 and m2 shall become mg each.
Hence at all instants the velocity of m1 and m2 shall be same
∴ The spring shall always remain in natural length.
As a > mg the acceleration of m1 and m2 shall become mg each.
Hence at all instants the velocity of m1 and m2 shall be same
∴ The spring shall always remain in natural length.
Create a free account to view solution
View Solution FreeMore Friction Questions
A chain of length L is placed on a horizontal surface as shown in figure. At any instant x is the length of chain on rou...A smooth block is released at rest on a 45o incline and then slides a distance d. The time taken to slide is n times as ...A bicycle is in motion. The force of friction exerted by the ground on its wheel is such that it acts :...A block of mass m lying on a rough horizontal plane is acted upon by a horizontal force P and another force Q inclined a...If you want to pile up sand onto a circular area of radius R. The greatest height of the sand pile that can be erected w...