A-block-of-mass-M-is-placed-on-smooth-ground-Its-upper-surface-is-smooth-and-vertical-surface-is-rough-with-coefficient-of-friction-A-block-of-mass-m-1-is-placed-on-its-horizontal-surface-and-tie

Question Number 21564 by Tinkutara last updated on 27/Sep/17

A block of mass M is placed on smooth

ground . Its upper surface is smooth and

vertical surface is rough with coefficient

of friction μ . A block of mass m_{1} is placed

on its horizontal surface and tied with

a massless inextensible string passing

over smooth pulley . Its other end is

connected to another block of mass m_{2},

which touches the vertical surface of

block M . Now a horizontal force F

starts acting on it .

Q 1 . Which of the following is incorrect

about above system ?

(1) There exists a value of F at which

friction force is equal to zero

(2) When F = 0, the blocks cannot

remain stationary

(3) There exists two limiting values of

F at which the blocks m_{1} and m_{2} will

remain stationary w . r . t . block of mass

M

(4) The limiting friction between m_{2}

and M is independent of F

Q 2 . In the above case, let m_{1} - μ m_{2} be

greater than 1 . Choose the incorrect

value of F for which the blocks m_{1} and

m_{2} remain stationary with respect to

M

(1) (M + m_{1} + m_{2}) \frac{m_{2} g}{m_{1}}

(2) \frac{m_{2} (M + m_{1} + m_{2})}{(m_{1} - μ m_{2})} g

(3) \frac{(M + m_{1} + m_{2}) m_{2} g}{(m_{1} + μ m_{2})}

(4) (M + m_{1} + m_{2}) \frac{g}{μ}

Q 3 . Let vertical part of block M be

smooth . Choose the correct alternative

(1) There exist two limiting values for

system to remain relatively at rest

(2) For one unique value of F, the blocks

m_{1} and m_{2} remain stationary with

respect to block M

(3) The blocks m_{1} and m_{2} cannot be in

equilibrium for any value of F

(4) There exists a range of mass M, for

which system remains stationary

Commented by Tinkutara last updated on 27/Sep/17