Question

Two blocks A and B of the same mass are joined by a light string and placed on a horizontal surface. An external horizontal force P acts on A. The tension in the string is T. The forces of friction acting on A and B are F1 and F2 respectively. The limiting value of F1 and F2 is F0 . As P is gradually increased,

Answer 1

Answer:

Case (I) for P<F0 , all the force will be opposed by friction on block A hence no tension in the string.

Case (II) for P<2F0 , forced cancelled by a block friction is F0 and rest of force is opposed by friction of second block. so tension in string is friction on B =P−F0

Case (III) for P>2F0 , T= force  for  accln. of  B + force  of  friction  on  B 

 T=2MP−2F0×M+F0=2P

Answer 2

Answer:

Case (I) for P<F0

, all the force will be opposed by friction on block A hence no tension in the string.

Case (II) for P<2F0

, forced cancelled by a block friction is F

0

and rest of force is opposed by friction of second block. so tension in string is friction on B =P−F0

Case (III) for P>2F0

, T= force  for  accln. of  B + force  of  friction  on  B 

 T=

2MP−2F0 ×M+F 0

= 2P