Two-Block Problems

IMPORTANT

Two-Block Problems: Overview

This topic covers concepts, such as, Motion of Two Blocks on Horizontal Plane, Motion of Two Blocks on Inclined Plane, Condition for Relative Motion between Two Blocks & Motion of Two Blocks in Contact etc.

Important Questions on Two-Block Problems

HARD
IMPORTANT

Two blocks connected by a massless string slide down an inclined plane having an angle of inclination of   37°.  The masses of the two blocks are   M 1 =4kg  and   M 2 =2kg  respectively and the coefficients of friction of   M 1 and   M 2 with the inclined plane are 0.75 and 0.25 respectively. Assuming the string to the taut, find the tension in the string.   ( sin37°=0.6,cos37°=0.8 )

HARD
IMPORTANT

Two blocks connected by a massless string slide down an inclined plane having an angle of inclination of 37°. The masses of the two blocks are M1=4 kg and M2=2 kg respectively and the coefficients of friction of M1 and M2 with the inclined plane are 0.75 and 0.25 respectively. Assuming the string to be taut, find the common acceleration of two masses. sin37°=0.6, cos37°=0.8

MEDIUM
IMPORTANT

Two blocks of masses M=5 kg and m=3 kg are placed on a horizontal surface as shown in fig. The coefficient of friction between the blocks is 0.5 and that between the block M and the horizontal surface is 0.7. What is the maximum horizontal force F that can be applied to block M so that the two blocks move without slipping ? Take g=10 m/s2

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HARD
IMPORTANT

Blocks A and B are arranged as shown in the figure. The pulley is frictionless. The mass of A is 10 kg. The coefficient of friction between the block A and the horizontal surface is 0.20. The minimum mass of B, to start the motion, will be

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HARD
IMPORTANT

A block of mass m=2 kg is placed on a plank of mass M=10 kg, which is placed on a smooth horizontal plane, as shown in the figure. The coefficient of friction between the block and the plank is μ=13. If a horizontal force F is applied on the plank, then the maximum value of F for which the block and the plank move together is g=10 m/s2

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MEDIUM
IMPORTANT

In the arrangement shown in the figure, if the blocks of masses m and 2 m are released from the state of rest, tension in the string is (μ= coefficient of friction, string is massless and inextensible, pulley is frictionless)

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EASY
IMPORTANT

In the situation shown, the reading of the spring balance is g=10 m s-2

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MEDIUM
IMPORTANT

Block 1 sits on top of block 2 . Both of them have a mass of 1 kg. The coefficients of friction between blocks 1 and 2 are μs=0.75 and μk=0.60. The table is frictionless. A force P2 is applied on block 1 to the left, and force P on block 2 to the right. Obtain the minimum value of P=Pmin such that both blocks move relative to each other and fill Pmin2 in OMR.

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MEDIUM
IMPORTANT

If F force is applied to 10 kg block as shown in diagram then maximum value of F so that there is no relative motion between the blocks.

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MEDIUM
IMPORTANT

Calculate the accelerations of the blocks A and B:-

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MEDIUM
IMPORTANT

A force of 0.5 N is applied on the upper block as shown in figure. The coefficient of static friction between the two blocks is 0.1 and that between the lower block and the surface is zero. The work done by the lower block on the upper block for a displacement of 3 m of the upper block is :-

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EASY
IMPORTANT

In friction is present between A & B only and F> limiting friction between A & B. Find acceleration of A & B.

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HARD
IMPORTANT

Two blocks connected by a massless string slides down an inclined plane having an angle of inclination of 37°. The masses of the two blocks are M1 = 4 kg and M2 = 2 kg respectively and the coefficients of friction of M1 and M2 with the inclined plane are 0.75 and 0.25 respectively. Assuming the string to be taut, find the common acceleration of two masses

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HARD
IMPORTANT

A block of mass m sits on the top of a block of mass 2m which sits on a table. The coefficient of kinetic friction between all surface is μ = 1 . A massless string is connected to each mass and wraps halfway around a massless pulley, as shown. Assume that you pull on the pulley with a force of 6mg. The acceleration of your hand is -
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EASY
IMPORTANT

Two blocks masses 1 kg and 2 kg rest on a smooth horizontal table. When the 2 kg block is pulled by a certain force F, the tension T in the string is 1.5 N. The value of F is


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MEDIUM
IMPORTANT

A 40 kg slab rests on a frictionless floor. A 10 kg block rests on top of the slab. The static coefficient of friction between the block and the slab is 0.60 while the kinetic coefficient of friction is 0.40. The 10 kg block is acted upon by a horizontal force of 100 N. If g=9.8 ms-2, the resulting acceleration of the slab will be


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MEDIUM
IMPORTANT

Two blocks of masses 3m and 2m are in contact on a smooth table. A force P is first applied horizontally on a block of mass 3m and then on mass 2 m. The contact forces between the two blocks in the two cases are in the ratio


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HARD
IMPORTANT

Block A of mass 2 kg is placed over a block B of mass 8 kg. The combination is placed on a rough horizontal surface. If g=10ms-2, coefficient of friction between B and floor =0.5, coefficient of friction between A and B = 0.4 and a horizontal force of 10 N is applied on 8 kg block, then the force of friction between A and B is


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MEDIUM
IMPORTANT

A block P of mass m is placed on a horizontal surface. Another block Q of same mass is kept on P and connected to the wall with the help of a spring of spring constant k as shown in the figure. μs is the coefficient of friction between P and Q. The blocks move together performing SHM of amplitude A. The maximum value of the friction force between P and Q is
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EASY
IMPORTANT

Block A of mass 2 kg is placed over block B of mass 8 kg. The combination is placed over a rough horizontal surface. Coefficient of friction between B and the floor is 0.5. Coefficient of friction between A and B is 0.4. A horizontal force of 10 N is applied on block B. The force of friction between A and B is
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