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question_answer1)
A body of mass m is moving in a circle of radius r with a constant speed v. The force on the body is \[\frac{m{{v}^{2}}}{r}\] and is directed towards the centre. What is the work done by this force in moving the body over half the circumference of the circle [NCERT 1977]
A)
\[\frac{m{{v}^{2}}}{\pi {{r}^{2}}}\] done
clear
B)
Zero done
clear
C)
\[\frac{m{{v}^{2}}}{{{r}^{2}}}\] done
clear
D)
\[\frac{\pi {{r}^{2}}}{m{{v}^{2}}}\] done
clear
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question_answer2)
If the unit of force and length each be increased by four times, then the unit of energy is increased by [CPMT 1987]
A)
16 times done
clear
B)
8 times done
clear
C)
2 times done
clear
D)
4 times done
clear
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question_answer3)
A man pushes a wall and fails to displace it. He does [CPMT 1992]
A)
Negative work done
clear
B)
Positive but not maximum work done
clear
C)
No work at all done
clear
D)
Maximum work done
clear
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question_answer4)
The same retarding force is applied to stop a train. The train stops after 80 m. If the speed is doubled, then the distance will be [CPMT 1984]
A)
The same done
clear
B)
Doubled done
clear
C)
Halved done
clear
D)
Four times done
clear
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question_answer5)
A body moves a distance of 10 m along a straight line under the action of a force of 5 N. If the work done is 25 joules, the angle which the force makes with the direction of motion of the body is [NCERT 1980; JIPMER 1997; CBSE PMT 1999; BHU 2000; RPMT 2000; Orissa JEE 2002]
A)
\[0{}^\circ \] done
clear
B)
\[30{}^\circ \] done
clear
C)
\[60{}^\circ \] done
clear
D)
\[90{}^\circ \] done
clear
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question_answer6)
You lift a heavy book from the floor of the room and keep it in the book-shelf having a height 2 m. In this process you take 5 seconds. The work done by you will depend upon [MP PET 1993]
A)
Mass of the book and time taken done
clear
B)
Weight of the book and height of the book-shelf done
clear
C)
Height of the book-shelf and time taken done
clear
D)
Mass of the book, height of the book-shelf and time taken done
clear
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question_answer7)
A body of mass m kg is lifted by a man to a height of one metre in 30 sec. Another man lifts the same mass to the same height in 60 sec. The work done by them are in the ratio [MP PMT 1993]
A)
\[1:2\] done
clear
B)
1 : 1 done
clear
C)
2 : 1 done
clear
D)
4 : 1 done
clear
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question_answer8)
A force \[F=(5\hat{i}+3\hat{j})\] newton is applied over a particle which displaces it from its origin to the point \[r=(2\hat{i}-1\hat{j})\] metres. The work done on the particle is [MP PMT 1995; RPET 2003]
A)
? 7 joules done
clear
B)
+ 13 joules done
clear
C)
+ 7 joules done
clear
D)
+ 11 joules done
clear
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question_answer9)
A force acts on a 30 gm particle in such a way that the position of the particle as a function of time is given by \[x=3t-4{{t}^{2}}+{{t}^{3}}\], where x is in metres and t is in seconds. The work done during the first 4 seconds is [CBSE PMT 1998]
A)
5.28 J done
clear
B)
450 mJ done
clear
C)
490 mJ done
clear
D)
530 mJ done
clear
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question_answer10)
A body of mass 10 kg is dropped to the ground from a height of 10 metres. The work done by the gravitational force is \[(g=9.8\,m/{{\sec }^{2}})\] [SCRA 1994]
A)
? 490 Joules done
clear
B)
+ 490 Joules done
clear
C)
? 980 Joules done
clear
D)
+ 980 Joules done
clear
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question_answer11)
Which of the following is a scalar quantity [AFMC 1998]
A)
Displacement done
clear
B)
Electric field done
clear
C)
Acceleration done
clear
D)
Work done
clear
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question_answer12)
The work done in pulling up a block of wood weighing 2 kN for a length of 10m on a smooth plane inclined at an angle of \[15{}^\circ \] with the horizontal is [AFMC 1999; Pb PMT 2003]
A)
4.36 kJ done
clear
B)
5.17 Kj done
clear
C)
8.91 kJ done
clear
D)
9.82 kJ done
clear
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question_answer13)
A force \[\vec{F}=5\hat{i}+6\hat{j}-4\hat{k}\] acting on a body, produces a displacement \[\vec{s}=6\vec{i}+5\vec{k}.\] Work done by the force is [KCET 1999]
A)
18 units done
clear
B)
15 units done
clear
C)
12 units done
clear
D)
10 units done
clear
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question_answer14)
A force of 5 N acts on a 15 kg body initially at rest. The work done by the force during the first second of motion of the body is [JIPMER 1999]
A)
5 J done
clear
B)
\[\frac{5}{6}J\] done
clear
C)
6 J done
clear
D)
\[75\,J\] done
clear
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question_answer15)
A force of 5 N, making an angle \[\theta \] with the horizontal, acting on an object displaces it by \[0.4m\] along the horizontal direction. If the object gains kinetic energy of 1J, the horizontal component of the force is [EAMCET (Engg.) 2000]
A)
1.5 N done
clear
B)
2.5 N done
clear
C)
3.5 N done
clear
D)
4.5 N done
clear
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question_answer16)
The work done against gravity in taking 10 kg mass at 1m height in 1sec will be [RPMT 2000]
A)
49 J done
clear
B)
98 J done
clear
C)
196 J done
clear
D)
None of these done
clear
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question_answer17)
The energy which an \[{{e}^{-}}\] acquires when accelerated through a potential difference of 1 volt is called [UPSEAT 2000]
A)
1 Joule done
clear
B)
1 Electron volt done
clear
C)
1 Erg done
clear
D)
1 Watt. done
clear
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question_answer18)
A body of mass 6kg is under a force which causes displacement in it given by \[S=\frac{{{t}^{2}}}{4}\] metres where t is time. The work done by the force in 2 seconds is [EAMCET 2001]
A)
12 J done
clear
B)
9 J done
clear
C)
6 J done
clear
D)
3 J done
clear
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question_answer19)
A body of mass 10kg at rest is acted upon simultaneously by two forces 4 N and 3N at right angles to each other. The kinetic energy of the body at the end of 10 sec is [Kerala (Engg.) 2001]
A)
100 J done
clear
B)
300 J done
clear
C)
50 J done
clear
D)
125 J done
clear
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question_answer20)
A cylinder of mass 10kg is sliding on a plane with an initial velocity of 10m/s. If coefficient of friction between surface and cylinder is 0.5, then before stopping it will describe [Pb. PMT 2001]
A)
12.5 m done
clear
B)
5 m done
clear
C)
7.5 m done
clear
D)
10 m done
clear
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question_answer21)
A force of \[(3\,\hat{i}+4\,\hat{j})\] Newton acts on a body and displaces it by \[(3\,\hat{i}+4\hat{j})\,m.\] The work done by the force is [AIIMS 2001]
A)
10 J done
clear
B)
12 J done
clear
C)
16 J done
clear
D)
25 J done
clear
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question_answer22)
A 50kg man with 20kg load on his head climbs up 20 steps of 0.25m height each. The work done in climbing is [JIPMER 2002]
A)
5 J done
clear
B)
350 J done
clear
C)
100 J done
clear
D)
3430 J done
clear
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question_answer23)
A force \[\overrightarrow{F\,}=6\hat{i}+2\hat{j}-3\hat{k}\] acts on a particle and produces a displacement of \[\overrightarrow{s\,}=2\hat{i}-3\hat{j}+x\hat{k}.\] If the work done is zero, the value of x is [Kerala PMT 2002]
A)
? 2 done
clear
B)
1/2 done
clear
C)
6 done
clear
D)
2 done
clear
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question_answer24)
A particle moves from position \[{{\vec{r}}_{1}}=\,3\hat{i}+2\hat{j}-6\hat{k}\] to position \[{{\vec{r}}_{2}}=14\hat{i}+13\hat{j}+9\hat{k}\] under the action of force \[4\hat{i}+\hat{j}+3\hat{k}\,N.\] The work done will be [Pb. PMT 2002,03]
A)
100 J done
clear
B)
50 J done
clear
C)
200 J done
clear
D)
75 J done
clear
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question_answer25)
A force \[(\vec{F})=3\hat{i}+c\hat{j}+2\hat{k}\] acting on a particle causes a displacement: \[(\vec{s})\,=-4\hat{i}+2\hat{j}+3\hat{k}\] in its own direction. If the work done is \[6\,J,\] then the value of \['c'\]is [CBSE PMT 2002]
A)
0 done
clear
B)
1 done
clear
C)
6 done
clear
D)
12 done
clear
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question_answer26)
In an explosion a body breaks up into two pieces of unequal masses. In this [MP PET 2002]
A)
Both parts will have numerically equal momentum done
clear
B)
Lighter part will have more momentum done
clear
C)
Heavier part will have more momentum done
clear
D)
Both parts will have equal kinetic energy done
clear
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question_answer27)
Which of the following is a unit of energy [AFMC 2002]
A)
Unit done
clear
B)
Watt done
clear
C)
Horse Power done
clear
D)
None done
clear
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question_answer28)
If force and displacement of particle in direction of force are doubled. Work would be [AFMC 2002]
A)
Double done
clear
B)
4 times done
clear
C)
Half done
clear
D)
\[\frac{1}{4}\]times done
clear
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question_answer29)
A body of mass 5 kg is placed at the origin, and can move only on the x-axis. A force of 10 N is acting on it in a direction making an angle of \[{{60}^{o}}\] with the x-axis and displaces it along the x-axis by 4 metres. The work done by the force is [MP PET 2003]
A)
2.5 J done
clear
B)
7.25 J done
clear
C)
40 J done
clear
D)
20 J done
clear
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question_answer30)
A force \[\overrightarrow{F}=(5\hat{i}+4\hat{j})\] N acts on a body and produces a displacement \[\overrightarrow{S}=(6\hat{i}-5\hat{j}+3\hat{k})\]m. The work done will be [CPMT 2003]
A)
10 J done
clear
B)
20 J done
clear
C)
30 J done
clear
D)
40 J done
clear
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question_answer31)
A uniform chain of length 2m is kept on a table such that a length of 60cm hangs freely from the edge of the table. The total mass of the chain is 4kg. What is the work done in pulling the entire chain on the table [AIEEE 2004]
A)
7.2 J done
clear
B)
3.6 J done
clear
C)
120 J done
clear
D)
1200 J done
clear
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question_answer32)
A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle, the motion of the particle takes place in a plane. It follows that [AIEEE 2004]
A)
Its velocity is constant done
clear
B)
Its acceleration is constant done
clear
C)
Its kinetic energy is constant done
clear
D)
It moves in a straight line done
clear
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question_answer33)
A ball of mass m moves with speed v and strikes a wall having infinite mass and it returns with same speed then the work done by the ball on the wall is [BCECE 2004]
A)
Zero done
clear
B)
\[mv\ J\] done
clear
C)
m/v J done
clear
D)
v/mJ done
clear
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question_answer34)
A force \[\vec{F}=(5\hat{i}+3\hat{j}+2\hat{k})N\] is applied over a particle which displaces it from its origin to the point \[\vec{r}=(2\hat{i}-\hat{j})m\]. The work done on the particle in joules is [AIEEE 2004]
A)
? 7 done
clear
B)
+7 done
clear
C)
+10 done
clear
D)
+13 done
clear
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question_answer35)
The kinetic energy acquired by a body of mass m is travelling some distance s, starting from rest under the actions of a constant force, is directly proportional to [Pb. PET 2000]
A)
\[{{m}^{0}}\] done
clear
B)
m done
clear
C)
\[{{m}^{2}}\] done
clear
D)
\[\sqrt{m}\] done
clear
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question_answer36)
If a force \[\vec{F}=4\hat{i}+5\hat{j}\] causes a displacement \[\vec{s}=3\hat{i}+6\hat{k}\], work done is [Pb. PET 2002]
A)
\[4\times 6\] unit done
clear
B)
\[6\times 3\]unit done
clear
C)
\[5\times 6\]unit done
clear
D)
\[4\times 3\]unit done
clear
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question_answer37)
A man starts walking from a point on the surface of earth (assumed smooth) and reaches diagonally opposite point. What is the work done by him [DCE 2004]
A)
Zero done
clear
B)
Positive done
clear
C)
Negative done
clear
D)
Nothing can be said done
clear
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question_answer38)
It is easier to draw up a wooden block along an inclined plane than to haul it vertically, principally because [CPMT 1977; JIPMER 1997]
A)
The friction is reduced done
clear
B)
The mass becomes smaller done
clear
C)
Only a part of the weight has to be overcome done
clear
D)
?g? becomes smaller done
clear
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question_answer39)
Two bodies of masses 1 kg and 5 kg are dropped gently from the top of a tower. At a point 20 cm from the ground, both the bodies will have the same [SCRA 1998]
A)
Momentum done
clear
B)
Kinetic energy done
clear
C)
Velocity done
clear
D)
Total energy done
clear
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question_answer40)
Due to a force of \[(6\hat{i}+2\hat{j})N\] the displacement of a body is \[(3\hat{i}-\hat{j})m\], then the work done is [Orissa JEE 2005]
A)
16 J done
clear
B)
12 J done
clear
C)
8 J done
clear
D)
Zero done
clear
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question_answer41)
A ball is released from the top of a tower. The ratio of work done by force of gravity in first, second and third second of the motion of the ball is [Kerala PET 2005]
A)
1 : 2 : 3 done
clear
B)
1 : 4 : 9 done
clear
C)
1 : 3 : 5 done
clear
D)
1 : 5 : 3 done
clear
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