
The weight of an aeroplane flying in the air is balanced by [NCERT 1974]
A)
Vertical component of the thrust created by air currents striking the lower surface of the wings done
clear
B)
Force due to reaction of gases ejected by the revolving propeller done
clear
C)
Upthrust of the air which will be equal to the weight of the air having the same volume as the plane done
clear
D)
Force due to the pressure difference between the upper and lower surfaces of the wings created by different air speeds on the surfaces done
clear
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When a body is stationary [NCERT 1978]
A)
There is no force acting on it done
clear
B)
The force acting on it is not in contact with it done
clear
C)
The combination of forces acting on it balances each other done
clear
D)
The body is in vacuum done
clear
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Two forces of magnitude F have a resultant of the same magnitude F. The angle between the two forces is [CBSE PMT 1990]
A)
\[45{}^\circ \] done
clear
B)
\[120{}^\circ \] done
clear
C)
\[150{}^\circ \] done
clear
D)
\[{{60}^{\text{o}}}\] done
clear
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Two forces with equal magnitudes F act on a body and the magnitude of the resultant force is F/3. The angle between the two forces is [MP PMT 1999]
A)
\[{{\cos }^{1}}\left( \frac{17}{18} \right)\] done
clear
B)
\[{{\cos }^{1}}\left( \frac{1}{3} \right)\] done
clear
C)
\[{{\cos }^{1}}\left( \frac{2}{3} \right)\] done
clear
D)
\[{{\cos }^{1}}\left( \frac{8}{9} \right)\] done
clear
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An object is subjected to a force in the northeast direction. To balance this force, a second force should be applied in the direction [KCET 1994]
A)
NorthEast done
clear
B)
South done
clear
C)
SouthWest done
clear
D)
West done
clear
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The resultant force of 5 N and 10 N cannot be [RPET 2000]
A)
12 N done
clear
B)
8 N done
clear
C)
4 N done
clear
D)
5 N done
clear
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The resultant of two forces \[3P\] and \[2P\]is R. If the first force is doubled then the resultant is also doubled. The angle between the two forces is [KCET 2001]
A)
\[{{60}^{\text{o}}}\] done
clear
B)
\[{{120}^{o}}\] done
clear
C)
\[{{70}^{o}}\] done
clear
D)
\[{{180}^{o}}\] done
clear
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The resultant of two forces, one double the other in magnitude, is perpendicular to the smaller of the two forces. The angle between the two forces is [KCET 2002]
A)
\[{{60}^{\text{o}}}\] done
clear
B)
\[{{120}^{\text{o}}}\] done
clear
C)
\[{{150}^{\text{o}}}\] done
clear
D)
\[{{90}^{\text{o}}}\] done
clear
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Two forces are such that the sum of their magnitudes is 18 N and their resultant is perpendicular to the smaller force and magnitude of resultant is 12 N. Then the magnitudes of the forces are [AIEEE 2002]
A)
12 N, 6 N done
clear
B)
13 N, 5N done
clear
C)
10 N, 8 N done
clear
D)
16 N, 2 N done
clear
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Which of the four arrangements in the figure correctly shows the vector addition of two forces \[\overrightarrow{{{F}_{1}}}\] and \[\overrightarrow{{{F}_{2}}}\] to yield the third force \[\overrightarrow{{{F}_{3}}}\] [Orissa JEE 2003]
A)
B)
C)
D)
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Which of the following sets of concurrent forces may be in equilibrium [KCET 2003]
A)
\[{{F}_{1}}=3N,\,\,{{F}_{2}}=5N,\,\,{{F}_{3}}=9N\] done
clear
B)
\[{{F}_{1}}=3N,\,\,{{F}_{2}}=5N,\,\,{{F}_{3}}=1N\] done
clear
C)
\[{{F}_{1}}=3N,\,{{F}_{2}}=5N,\,{{F}_{3}}=15N\] done
clear
D)
\[{{F}_{1}}=3N,\,\,{{F}_{2}}=5N,\,\,{{F}_{3}}=6N\] done
clear
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Three forces starts acting simultaneously on a particle moving with velocity \[\vec{v}.\] These forces are represented in magnitude and direction by the three sides of a triangle ABC (as shown). The particle will now move with velocity [AIEEE 2003]
A)
\[\overrightarrow{v\,}\] remaining unchanged done
clear
B)
Less than \[\overrightarrow{v\,}\] done
clear
C)
Greater than \[\overrightarrow{v\,}\] done
clear
D)
\[\overrightarrow{v\,}\] in the direction of the largest force BC done
clear
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Which of the following groups of forces could be in equibrium [UPSEAT 2004]
A)
3 N, 4 N, 5 N done
clear
B)
4N, 5 N, 10 N done
clear
C)
30N, 40 N, 80 N done
clear
D)
1N, 3 N, 5 N done
clear
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Two blocks are connected by a string as shown in the diagram. The upper block is hung by another string. A force F applied on the upper string produces an acceleration of \[2m/{{s}^{2}}\] in the upward direction in both the blocks. If T and \[{T}'\] be the tensions in the two parts of the string, then [AMU (Engg.) 2000]
A)
\[T=70.8N\] and \[{T}'=47.2N\] done
clear
B)
\[T=58.8N\] and \[{T}'=47.2N\] done
clear
C)
\[T=70.8N\] and \[{T}'=58.8N\] done
clear
D)
\[T=70.8N\] and \[{T}'=0\] done
clear
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Consider the following statements about the blocks shown in the diagram that are being pushed by a constant force on a frictionless table [AMU (Engg.) 2001]
A. All blocks move with the same acceleration B. The net force on each block is the same. Which of these statements are/is correct
A)
A only done
clear
B)
B only done
clear
C)
Both A and B done
clear
D)
Neither A nor B done
clear
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If two forces of 5 N each are acting along X and Y axes, then the magnitude and direction of resultant is [DCE 2004]
A)
\[5\sqrt{2},\,\,\pi /3\] done
clear
B)
\[5\sqrt{2},\,\,\pi /4\] done
clear
C)
\[5\sqrt{2},\,\,\pi /3\] done
clear
D)
\[5\sqrt{2},\,\,\pi /4\] done
clear
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Which of the following is the correct order of forces [AIEEE 2002]
A)
Weak < gravitational forces < strong forces (nuclear) < electrostatic done
clear
B)
Gravitational < weak < (electrostatic) < strong force done
clear
C)
Gravitational < electrostatic < weak < strong force done
clear
D)
Weak < gravitational < electrostatic < strong forces done
clear
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A block is kept on a frictionless inclined surface with angle of inclination 'a'. The incline is given an acceleration 'a' to keep the block stationary. Then a is equal to [AIEEE 2005]
A)
\[g\] done
clear
B)
\[g\,tan\alpha \] done
clear
C)
\[g/\,tan\alpha \] done
clear
D)
\[g\,cosec\alpha \] done
clear
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