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question_answer1)
The coefficient of friction \[\mu \] and the angle of friction \[\lambda \] are related as
A)
\[\sin \lambda =\mu \] done
clear
B)
\[\cos \lambda =\mu \] done
clear
C)
\[\tan \lambda =\mu \] done
clear
D)
\[\tan \mu =\lambda \] done
clear
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question_answer2)
A force of 98 N is required to just start moving a body of mass 100 kg over ice. The coefficient of static friction is
A)
0.6 done
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B)
0.4 done
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C)
0.2 done
clear
D)
0.1 done
clear
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question_answer3)
A block weighs W is held against a vertical wall by applying a horizontal force F. The minimum value of F needed to hold the block is [MP PMT 1993]
A)
Less than W done
clear
B)
Equal to W done
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C)
Greater than W done
clear
D)
Data is insufficient done
clear
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question_answer4)
The maximum static frictional force is
A)
Equal to twice the area of surface in contact done
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B)
Independent of the area of surface in contact done
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C)
Equal to the area of surface in contact done
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D)
None of the above done
clear
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question_answer5)
Maximum value of static friction is called [BHU 1995; RPET 2000]
A)
Limiting friction done
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B)
Rolling friction done
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C)
Normal reaction done
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D)
Coefficient of friction done
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question_answer6)
Pulling force making an angle \[\theta \] to the horizontal is applied on a block of weight W placed on a horizontal table. If the angle of friction is \[\alpha \], then the magnitude of force required to move the body is equal to [EAMCET 1987]
A)
\[\frac{W\sin \alpha }{g\tan (\theta -\alpha )}\] done
clear
B)
\[\frac{W\cos \alpha }{\cos (\theta -\alpha )}\] done
clear
C)
\[\frac{W\sin \alpha }{\cos (\theta -\alpha )}\] done
clear
D)
\[\frac{W\tan \alpha }{\sin (\theta -\alpha )}\] done
clear
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question_answer7)
In the figure shown, a block of weight 10 N resting on a horizontal surface. The coefficient of static friction between the block and the surface \[{{\mu }_{s}}=0.4\]. A force of 3.5 N will keep the block in uniform motion, once it has been set in motion. A horizontal force of 3 N is applied to the block, then the block will [MP PET 1993]
A)
Move over the surface with constant velocity done
clear
B)
Move having accelerated motion over the surface done
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C)
Not move done
clear
D)
First it will move with a constant velocity for some time and then will have accelerated motion done
clear
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question_answer8)
Two masses A and B of 10 kg and 5 kg respectively are connected with a string passing over a frictionless pulley fixed at the corner of a table as shown. The coefficient of static friction of A with table is 0.2. The minimum mass of C that may be placed on A to prevent it from moving is [MP PET 1984]
A)
15 kg done
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B)
10 kg done
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C)
5 kg done
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D)
12 kg done
clear
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question_answer9)
The limiting friction is
A)
Always greater than the dynamic friction done
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B)
Always less than the dynamic friction done
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C)
Equal to the dynamic friction done
clear
D)
Sometimes greater and sometimes less than the dynamic friction done
clear
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question_answer10)
Which is a suitable method to decrease friction
A)
Ball and bearings done
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B)
Lubrication done
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C)
Polishing done
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D)
All the above done
clear
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question_answer11)
A uniform rope of length l lies on a table. If the coefficient of friction is \[\mu \], then the maximum length \[{{l}_{1}}\] of the part of this rope which can overhang from the edge of the table without sliding down is [DPMT 2001]
A)
\[\frac{l}{\mu }\] done
clear
B)
\[\frac{l}{\mu +l}\] done
clear
C)
\[\frac{\mu l}{1+\mu }\] done
clear
D)
\[\frac{\mu l}{\mu -1}\] done
clear
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question_answer12)
Which of the following statements is not true [CMC Vellore 1989]
A)
The coefficient of friction between two surfaces increases as the surface in contact are made rough done
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B)
The force of friction acts in a direction opposite to the applied force done
clear
C)
Rolling friction is greater than sliding friction done
clear
D)
The coefficient of friction between wood and wood is less than 1 done
clear
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question_answer13)
A block of 1 kg is stopped against a wall by applying a force F perpendicular to the wall. If \[\mu =0.2\] then minimum value of F will be [MP PMT 2003]
A)
980 N done
clear
B)
49 N done
clear
C)
98 N done
clear
D)
490 N done
clear
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question_answer14)
A heavy uniform chain lies on a horizontal table-top. If the coefficient of friction between the chain and table surface is 0.25, then the maximum fraction of length of the chain, that can hang over one edge of the table is [CBSE PMT 1990]
A)
20% done
clear
B)
25% done
clear
C)
35% done
clear
D)
15% done
clear
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question_answer15)
The 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 of A with the horizontal surface is 0.20. The minimum mass of B to start the motion will be [MP PET 1994]
A)
2 kg done
clear
B)
0.2 kg done
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C)
5 kg done
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D)
10 kg done
clear
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question_answer16)
Work done by a frictional force is
A)
Negative done
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B)
Positive done
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C)
Zero done
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D)
All of the above done
clear
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question_answer17)
A uniform chain of length L changes partly from a table which is kept in equilibrium by friction. The maximum length that can withstand without slipping is l, then coefficient of friction between the table and the chain is [EAMCET (Engg.) 1995]
A)
\[\frac{l}{L}\] done
clear
B)
\[\frac{l}{L+l}\] done
clear
C)
\[\frac{l}{L-l}\] done
clear
D)
\[\frac{L}{L+l}\] done
clear
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question_answer18)
When two surfaces are coated with a lubricant, then they [AFMC 1998, 99; AIIMS 2001]
A)
Stick to each other done
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B)
Slide upon each other done
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C)
Roll upon each other done
clear
D)
None of these done
clear
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question_answer19)
A 20 kg block is initially at rest on a rough horizontal surface. A horizontal force of 75 N is required to set the block in motion. After it is in motion, a horizontal force of 60 N is required to keep the block moving with constant speed. The coefficient of static friction is [AMU 1999]
A)
0.38 done
clear
B)
0.44 done
clear
C)
0.52 done
clear
D)
0.60 done
clear
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question_answer20)
A block A with mass 100 kg is resting on another block B of mass 200 kg. As shown in figure a horizontal rope tied to a wall holds it. The coefficient of friction between A and B is 0.2 while coefficient of friction between B and the ground is 0.3. The minimum required force F to start moving B will be [RPET 1999]
A)
900 N done
clear
B)
100 N done
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C)
1100 N done
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D)
1200 N done
clear
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question_answer21)
To avoid slipping while walking on ice, one should take smaller steps because of the [BHU 1999; BCECE 2004]
A)
Friction of ice is large done
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B)
Larger normal reaction done
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C)
Friction of ice is small done
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D)
Smaller normal reaction done
clear
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question_answer22)
A box is lying on an inclined plane what is the coefficient of static friction if the box starts sliding when an angle of inclination is 60o [KCET 2000]
A)
1.173 done
clear
B)
1.732 done
clear
C)
2.732 done
clear
D)
1.677 done
clear
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question_answer23)
A block of mass 2 kg is kept on the floor. The coefficient of static friction is 0.4. If a force F of 2.5 Newtons is applied on the block as shown in the figure, the frictional force between the block and the floor will be [MP PET 2000]
A)
2.5 N done
clear
B)
5 N done
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C)
7.84 N done
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D)
10 N done
clear
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question_answer24)
Which one of the following is not used to reduce friction [Kerala (Engg.) 2001]
A)
Oil done
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B)
Ball bearings done
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C)
Sand done
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D)
Graphite done
clear
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question_answer25)
If a ladder weighing 250N is placed against a smooth vertical wall having coefficient of friction between it and floor is 0.3, then what is the maximum force of friction available at the point of contact between the ladder and the floor [AIIMS 2002]
A)
75 N done
clear
B)
50 N done
clear
C)
35 N done
clear
D)
25 N done
clear
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question_answer26)
A body of mass 2 kg is kept by pressing to a vertical wall by a force of 100 N. The coefficient of friction between wall and body is 0.3. Then the frictional force is equal to [Orissa JEE 2003]
A)
6 N done
clear
B)
20 N done
clear
C)
600 N done
clear
D)
700 N done
clear
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question_answer27)
A horizontal force of 10 N is necessary to just hold a block stationary against a wall. The coefficient of friction between the block and the wall is 0.2. the weight of the block is [AIEEE 2003]
A)
2 N done
clear
B)
20 N done
clear
C)
50 N done
clear
D)
100 N done
clear
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question_answer28)
The coefficient of static friction, \[{{\mu }_{s}},\] between block A of mass 2 kg and the table as shown in the figure is 0.2. What would be the maximum mass value of block B so that the two blocks do not move? The string and the pulley are assumed to be smooth and massless. \[(g=10\,m/{{s}^{2}})\] [CBSE PMT 2004]
A)
2.0 kg done
clear
B)
4.0 kg done
clear
C)
0.2 kg done
clear
D)
0.4 kg done
clear
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question_answer29)
If mass of \[A=10\,\,kg\], coefficient of static friction = 0.2, coefficient of kinetic friction = 0.2. Then mass of B to start motion is [Orissa PMT 2004]
A)
2 kg done
clear
B)
2.2 kg done
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C)
4.8 kg done
clear
D)
200 gm done
clear
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question_answer30)
A uniform metal chain is placed on a rough table such that one end of chain hangs down over the edge of the table. When one-third of its length hangs over the edge, the chain starts sliding. Then, the coefficient of static friction is [Kerala PET 2005]
A)
\[\frac{3}{4}\] done
clear
B)
\[\frac{1}{4}\] done
clear
C)
\[\frac{2}{3}\] done
clear
D)
\[\frac{1}{2}\] done
clear
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question_answer31)
A lift is moving downwards with an acceleration equal to acceleration due to gravity. A body of mass m kept on the floor of the lift is pulled horizontally. If the coefficient of friction is m, then the frictional resistance offered by the body is [DPMT 2004]
A)
mg done
clear
B)
\[\mu mg\] done
clear
C)
\[2\mu mg\] done
clear
D)
Zero done
clear
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question_answer32)
If a ladder weighing 250 N is placed against a smooth vertical wall having coefficient of friction between it and floor is 0.3, then what is the maximum force of friction available at the point of contact between the ladder and the floor [BHU 2004]
A)
75 N done
clear
B)
50 N done
clear
C)
35 N done
clear
D)
25 N done
clear
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