# Mechanics Booster-3

1133
Sourish Ghosh ·

Force acting of block 2M is 2F towards left, and on M is F towards right. Thus net accln of system is F3M towards left.

Consider the COM of the system as the frame of reference.
Applying appropriate pseudo forces on each block,
F2M = 2F - 2M.F3M = 4F3 towards left.
FM = F + M.F3M = 4F3 towards rights.
Let the extensions caused by F2M and FM be x1 and x2.
Conserving energy,
F2Mx1 + FMx2 = 12k(x1 + x2)2 [At max extension, kinetic energy = 0]
=> (x1 + x2) = 8F3k

• Himanshu Giria just 1 doubt ... plz tel how are we applying energy conservation in the 2nd last equn.....
• Sourish Ghosh Work done by both the forces = potential energy stored in the spring.
• Akash Anand Excellent work Sourish..keep it up :)
11
Chandra Prakash Mishra ·

the force on M is F towards right whereas on the block 2M is2F towards left .net force=3F .exten.=3F/k

• Akash Anand Can you be anymore wrong ???
1161
Akash Anand ·

Hint for this question is another question, you might enjoy :)

466
Himanshu Giria ·

is't (B) ??