
question_answer1) A particle moves under the effect of a force \[F~=Cx\]from x = 0 to \[x={{x}_{1}}\]. The work done in the process is [CPMT 1982; DCE 2002;Orissa JEE 2005]
A) \[Cx_{1}^{2}\] done
clear
B) \[\frac{1}{2}Cx_{1}^{2}\] done
clear
C) \[C{{x}_{1}}\] done
clear
D) Zero done
clear
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question_answer2) A cord is used to lower vertically a block of mass M by a distance d with constant downward acceleration \[\frac{g}{4}\]. Work done by the cord on the block is [CPMT 1972]
A) \[Mg\frac{d}{4}\] done
clear
B) \[3Mg\frac{d}{4}\] done
clear
C) \[3Mg\frac{d}{4}\] done
clear
D) Mgd done
clear
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question_answer3) Two springs have their force constant as \[{{k}_{1}}\] and \[{{k}_{2}}({{k}_{1}}>{{k}_{2}})\]. When they are stretched by the same force [EAMCET 1981]
A) No work is done in case of both the springs done
clear
B) Equal work is done in case of both the springs done
clear
C) More work is done in case of second spring done
clear
D) More work is done in case of first spring done
clear
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question_answer4) A spring of force constant 10 N/m has an initial stretch 0.20 m. In changing the stretch to 0.25 m, the increase in potential energy is about [CPMT 1977]
A) 0.1 joule done
clear
B) 0.2 joule done
clear
C) 0.3 joule done
clear
D) 0.5 joule done
clear
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question_answer5) The potential energy of a certain spring when stretched through a distance ?S? is 10 joule. The amount of work (in joule) that must be done on this spring to stretch it through an additional distance ?S? will be [MNR 1991; CPMT 2002; UPSEAT 2000; Pb. PET 2004]
A) 30 done
clear
B) 40 done
clear
C) 10 done
clear
D) 20 done
clear
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question_answer6) Two springs of spring constants 1500 N/m and 3000 N/m respectively are stretched with the same force. They will have potential energy in the ratio [MP PMT/PET 1998; Pb. PMT 2002]
A) 4 : 1 done
clear
B) 1 : 4 done
clear
C) 2 : 1 done
clear
D) 1 : 2 done
clear
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question_answer7) A spring 40 mm long is stretched by the application of a force. If 10 N force required to stretch the spring through 1 mm, then work done in stretching the spring through 40 mm is [AIIMS 1998; AFMC 2000; JIPMER 2000]
A) 84 J done
clear
B) 68 J done
clear
C) 23 J done
clear
D) 8 J done
clear
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question_answer8) A position dependent force \[F=72x+3{{x}^{2}}\,newton\] acts on a small body of mass 2 kg and displaces it from \[x=0\] to \[x=5\,m\]. The work done in joules is [CBSE PMT 1994]
A) 70 done
clear
B) 270 done
clear
C) 35 done
clear
D) 135 done
clear
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question_answer9) A body of mass 3 kg is under a force, which causes a displacement in it is given by \[S=\frac{{{t}^{3}}}{3}\] (in m). Find the work done by the force in first 2 seconds [BHU 1998]
A) 2 J done
clear
B) 3.8 J done
clear
C) 5.2 J done
clear
D) 24 J done
clear
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question_answer10) The force constant of a wire is k and that of another wire is \[2k.\] When both the wires are stretched through same distance, then the work done [MH CET 2000]
A) \[{{W}_{2}}=2W_{1}^{2}\] done
clear
B) \[{{W}_{2}}=2{{W}_{1}}\] done
clear
C) \[{{W}_{2}}={{W}_{1}}\] done
clear
D) \[{{W}_{2}}=0.5{{W}_{1}}\] done
clear
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question_answer11) A body of mass 0.1 kg moving with a velocity of 10 m/s hits a spring (fixed at the other end) of force constant 1000 N/m and comes to rest after compressing the spring. The compression of the spring is [MP PMT 2001]
A) \[0.01\,m\] done
clear
B) \[0.1\,m\] done
clear
C) \[0.2\,m\] done
clear
D) \[0.5\,m\] done
clear
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question_answer12) When a 1.0kg mass hangs attached to a spring of length 50 cm, the spring stretches by 2 cm. The mass is pulled down until the length of the spring becomes 60 cm. What is the amount of elastic energy stored in the spring in this condition, if g = 10 m/s2 [MP PET 2001]
A) 1.5 Joule done
clear
B) 2.0 Joule done
clear
C) 2.5 Joule done
clear
D) 3.0 Joule done
clear
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question_answer13) A spring of force constant 800 N/m has an extension of 5cm. The work done in extending it from 5cm to 15 cm is [AIEEE 2002]
A) 16 J done
clear
B) 8 J done
clear
C) 32 J done
clear
D) 24 J done
clear
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question_answer14) When a spring is stretched by 2 cm, it stores 100 J of energy. If it is stretched further by 2 cm, the stored energy will be increased by [Orissa JEE 2002]
A) 100 J done
clear
B) 200 J done
clear
C) 300 J done
clear
D) 400 J done
clear
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question_answer15) A spring when stretched by 2 mm its potential energy becomes 4 J. If it is stretched by 10 mm, its potential energy is equal to [BCECE 2003]
A) 4 J done
clear
B) 54 J done
clear
C) 415 J done
clear
D) None done
clear
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question_answer16) A spring of spring constant 5 ? 103 N/m is stretched initially by 5cm from the unstretched position. Then the work required to stretch it further by another \[5cm\] is [AIEEE 2003]
A) 6.25 Nm done
clear
B) 12.50 Nm done
clear
C) 18.75 Nm done
clear
D) 25.00 Nm done
clear
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question_answer17) A mass of 0.5kg moving with a speed of 1.5 m/s on a horizontal smooth surface, collides with a nearly weightless spring of force constant \[k=50\ N/m\]. The maximum compression of the spring would be [CBSE PMT 2004]
A) 0.15 m done
clear
B) 0.12 m done
clear
C) 1.5 m done
clear
D) 0.5 m done
clear
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question_answer18) A particle moves in a straight line with retardation proportional to its displacement. Its loss of kinetic energy for any displacement x is proportional to [AIEEE 2004]
A) \[{{x}^{2}}\] done
clear
B) \[{{e}^{x}}\] done
clear
C) x done
clear
D) \[{{\log }_{e}}x\] done
clear
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question_answer19) A spring with spring constant k when stretched through 1 cm, the potential energy is U. If it is stretched by 4 cm. The potential energy will be [Orissa PMT 2004]
A) 4U done
clear
B) 8U done
clear
C) 16 U done
clear
D) 2U done
clear
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question_answer20) A spring with spring constant k is extended from \[x=0\]to\[x={{x}_{1}}\]. The work done will be [Orissa PMT 2004]
A) \[kx_{1}^{2}\] done
clear
B) \[\frac{1}{2}kx_{1}^{2}\] done
clear
C) \[2kx_{1}^{2}\] done
clear
D) \[2k{{x}_{1}}\] done
clear
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question_answer21) If a long spring is stretched by 0.02 m, its potential energy is U. If the spring is stretched by 0.1 m, then its potential energy will be [MP PMT 2002; CBSE PMT 2003; UPSEAT 2004]
A) \[\frac{U}{5}\] done
clear
B) \[U\] done
clear
C) 5U done
clear
D) 25U done
clear
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question_answer22) Natural length of a spring is 60 cm, and its spring constant is 4000 N/m. A mass of 20 kg is hung from it. The extension produced in the spring is, (Take \[g=9.8\ m/{{s}^{2}}\]) [DCE 2004]
A) 4.9 cm done
clear
B) 0.49 cm done
clear
C) 9.4 cm done
clear
D) 0.94 cm done
clear
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question_answer23) The spring extends by x on loading, then energy stored by the spring is : (if T is the tension in spring and k is spring constant) [Pb. PMT 2003]
A) \[\frac{{{T}^{2}}}{2k}\] done
clear
B) \[\frac{{{T}^{2}}}{2{{k}^{2}}}\] done
clear
C) \[\frac{2k}{{{T}^{2}}}\] done
clear
D) \[\frac{2{{T}^{2}}}{k}\] done
clear
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question_answer24) The potential energy of a body is given by, U =\[AB{{x}^{2}}\](Where x is the displacement). The magnitude of force acting on the particle is [BHU 2002]
A) Constant done
clear
B) Proportional to x done
clear
C) Proportional to \[{{x}^{2}}\] done
clear
D) Inversely proportional to x done
clear
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question_answer25) The potential energy between two atoms in a molecule is given by \[U(x)=\frac{a}{{{x}^{12}}}\frac{b}{{{x}^{6}}}\]; where a and b are positive constants and x is the distance between the atoms. The atom is in stable equilibrium when [CBSE PMT 1995]
A) \[x=\sqrt[6]{\frac{11a}{5b}}\] done
clear
B) \[x=\sqrt[6]{\frac{a}{2b}}\] done
clear
C) \[x=0\] done
clear
D) \[x=\sqrt[6]{\frac{2a}{b}}\] done
clear
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question_answer26) Which one of the following is not a conservative force [Kerala PMT 2005]
A) Gravitational force done
clear
B) Electrostatic force between two charges done
clear
C) Magnetic force between two magnetic dipoles done
clear
D) Frictional force done
clear
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