Test Review English Work

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PHYSICS COURSE(AIIMS/JEE (MAINS ADVANCE) /MPPET/MPPMT-2014) SARASWATIEDUCATIONAL INS

WORK ENERGY AND POWER CLASS TEST NO -3 September 09, 2013

1. A body of mass m kgis lifted by a man to a height

of one meter in 30 sec. Another man lifts the same

mass to the double height in 60 sec. The work

done by them are in the ratio

(a) 1:2 (b)1 : 1

(c) 2 : 1 (d) 4 : 12. A body of mass 3 kg is dropped to the ground

from a height of 10 metres. The work done by the

gravitational force is

(a) 490 J (b)+ 490 J

(c)980 J (d) + 300 J

3. A body of mass 999 kgis placed at the origin, and

can move only on the x-axis. A force of 1.25 N is

acting on it in a direction making an angle of o60

with the x-axis and displaces it along the x-axis by4 metres. The work done by the force is

(a) 2.5J (b)7.25J

(c) 40J (d) 20J

4. A uniform chain of length L and mass M is lying

on a smooth table and one sixth of its length is

hanging vertically down over the edge of the table.

If g is acceleration due to gravity, the work

required to pull the hanging part on to the table is

(a) MgL (b) (c)

(d)

5. The object moving with constant velocity on

frictionless surface then total work done is

(a) Negetive (b) Positive

(c) Zero (d) none

6. 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 ballis

(a) 1 : 2 : 3 (b) 1 : 4 : 9

(c) 1 : 3 : 5 (d) 1 : 5 : 3

7. A light and a heavy body have equal momenta.

Which one has greater K.E

(a) The light body (b) The heavy body

(c) The K.E. are equal (d) Data is incomplete

8. If the increase in the kinetic energy of a body

525% then the increase in the momentum will b

(a) 150% (b) 250%

(c) %300 (d) 265%

9. Two bodies A andB having masses in the ratio

4 : 1 possess the same kinetic energy. The ratiotheir linear moment is then

(a) 2: 1 (b) 4 : 1

(c) 1 : 2 (d) 16 : 1

10. in given figure pendulum of length l and mass

bob m is displaced from A to B then work done

gravity is

(a)2

mgl

(b)3

2mgl

(c) 2mgl (d)1

2mgl

11. A car moving with a velocity of 19 m/s can

stopped by the application of a constant force F

a distance of 12 m. If the velocity of the car is

m/s, it can be stopped by this force in

(a)19m (b)48 m

(c) 60 m (d) 24 m

12.

Which one of the following is not a conservatforce

(a) Gravitational force

(b) Electrostatic force between two charges

(c) Magnetic force between two magnetic dipole

(d) Frictional force

13. The potential energy of a body is given b

U = 28 (Where x is the displacement). The

force acting on the particle is

(a)16x (b)8x(c)x (d)-16x

14. The potential energy of a body is given b

U=2

8 4

r r The particle is in equilibrium when

(a) r =1 meter (b) r =1meter

(c) r =4 meter (d) r = Zero

60o

B

A

O


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15. The potential energy of a particle varies with

distancex as shown in the graph.

The force acting on the particle is zero at

(a) R (b) Q

(c) P and S (d) R and Q

16. Two springs have their force constant as 1k and

2 1 2( )k k k . When they are stretched by the same

force

(a) No work is done in case of both the springs

(b) Equal work is done in case of both the springs

(c)More work is done in case of second spring

(d) More work is done in case of first spring17. When a spring is stretched by 2 cm, it stores 300J

of energy. If it is stretched further by 2 cm, the

stored energy will be increased by

(a) 100J (b)200J

(c) 1200J (d) 900J

18. The block of mass 2kgmoving on the frictionless

horizontal surface collides with the spring of

spring constant 450N/m compresses is 10 cm ,then maximum velocity of mass is

(a)15 m/s

(b)1.5 cm/s K

(c)Zero

(d)150 cm/s

19. The block of mass m moving with velocity v on

the frictionless horizontal surface collides with the

spring of spring constant k then maximum

compresses is

(a) 8 .m vk

(b)

.8

kv

m v

(c)2m

vk

(d)

mv

k

20. when a pendulum of length l/2 and bob mass m

released at horizontal position then its velocity at

vertical position is

(a) 2gl (b) gl

(c) 3gl (d)zero

21. What is the velocity of the bob of a sim

pendulum at its mean position, if it is able to r

to vertical height of 45cm

(a) 0.6 m/s

(b) 1.4 m/s

(c) 1.8 m/s

(d)3 m/s

22. when a body of 2kg relies at point P(frictionles

Circular) to Q .Then find out its velocity on po

Q ( R=5m)

(a)v =10 m/s (b) v >10 m/s

(c) v


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27. A car of mass 1250 kg is moving at 30m/s. Its

engine delivers 30 kWwhile resistive force due to

surface is 1000N. What max acceleration can be

given in the car

(a) 2/3

1sm

(b) 2/

4

1sm

(c) 2/5

1sm

(d) Zero

28. The average force necessary to stop a bullet of

mass m moving with a speed of v , as it

penetrates into the wood for a distance of d is

(a)22mu

d (b)

2mu

d

(c)2

2

mu

d (d)

2

mu

d

29. A body at rest may have

(a) Energy

(b) Momentum

(c) Speed

(d) Velocity

30. A ball of mass m thrown vertically upwards

with velocity u by the hand of a person. In this

process his hand moved at a distance x in

upwards. work done by person is :-

(a)

()(b)

+

(c) (d)

31. Work done by the centepratical force F in one

complete cycle of circular path of radius 10 m is

(a)20 F (b) 20 F(c) 10 F (d) Zero

32. Object of m is slipping on frictionless

hemisphere of radius 1.8 m from its one endto bottom. Velocity of object of at lower

point is(a) 6 m/s (b) 12 m/s

(c) 4 m/s (d) 8 m/s

33. Dimensional formula of power is &

(a) M1 L2 T2 (b) M1 L1 T2

(c) M1 L2 T3 (d) M1 L1 T2

34. kis the force constant of a spring .The work don

In increasing its extension from l1 to l2 &

(a) ( ) (b) ( )(c) ( ) (d) ( + )

35. A body of mass 0.1 kgmoving with a velocity

10 m/s hits a spring (fixed at the other end)

force constant 1000 N/m and comes to rest af

compressing the spring. The compression of

spring is

(a) 0.01m (b) 0.1 m

(c) 0.2 m (d) 0.5 m

36. work done to displaced a block of mass 2 kg i

inclined plane at a height of 10 m is 300J .Th

work done against friction is [ 'g' =10 m/s2]

(a) 100 J (b) 200 J

(c) 300 J (d) Zero

37. Which of the following is not the unit of work

(a) Calorie (b) Joule

(c) Electron-Volt (d) Watt

38. The force constants of two springs are k1 and

respectively. Both are stretched till their potent

energies are equal .The forces F1 and F2 appliedthem are in the ratio

(a) k1 :k2 (b) k2 : k1

(c) (d)2 139. From a waterfall, water is falling down at the r

of 100 kg/s on the blades of turbine. If the heig

of the fall is 100 m, then the power delivered

the turbine is approximately equal to

(a) 100 kW (b) 10 kW(c) 1 kW (d) 1000 kW

40. If a object freely falling towards earth then its to

energy

(a) Increase

(b) Decrease

(c) constant

(d) Some time increase some time decrease


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41. Rate of water up lifting in kilogram per sec from a

bell of depth 7.46 meter by the machine of 5

horse power is :-

(a) 500 kg (b) 50gram

(c) 25 kg (d) 50 kg

42. A women pulling the box on the rough surface of

railway platform during the distance 10 m .she

applied constant force 100 N then after she

decreased force linearly up to 50 N.(further 10m

friction on box by surface is 50 N ). If total

displacement is 20 meter then work done by

women is

(a) 175 N (b) 1750 N

(c) 1500 N (d) 2000 N

43. A weightlifter lifts a weight off the ground and

holds it up

(a) Work is done in lifting as well as holding theweight

(b) No work is done in both lifting and holding the

weight

(c) No work is done in both lifting and holding the

weight

(d) No work is done in lifting the weight but work

is required to be done in holding it up

44. A rope ladder with a length lcarrying a man with

a mass m at its end is attached to the basket of aballoon with a mass M. The entire system is in

equilibrium in the air .As the man climbs up the

ladder in to the balloon, the balloon descends by a

height h. Then the potential energy of the man

(a) increases by mg(1-h)

(b) increases by mgl

(c) increases by mgh

(d) increases by mg (2l-h)

45. The potential energy of a 1kg particle free to move

along the x-axis is given by

() = 4 2

The total mechanical energy of the particle is

2J.Then the maximum speed (in m/s) is

(a)2 (b)

(c) (d) )

46. N similar slabs of cubical shape of edge b are lying

ground. Density of material of slab is D. Work done

arrange them one over the other is

(a) ( 1) (b) ( 1)(c) ( ) (d) ( )

47. In a childrens park, there is a slide which ha

total length of 10 m and a height of 8m .

vertical ladder is provided to reach the top. A bweighing 200 N climbs up the ladder to the top

the slide and slides down to the ground. T

average friction offered by the slide is three te

of his weight .Then :

(a) The Work done by ladder on the boy as he

goes up is zero

(b) The Work done by ladder on the boy as he

goes up is 1600 J

(c) The Work done by slide on the boy as he

comes down is 600 (d) The Work done by gravity on the boy as he

comes down is 1600 48. A smooth track in from of a quarter circle

radius 6 m lies in the vertical plane. A parti

moves from P1 to P2 under the action of forces

, and . Force is always towards P2 ais always 20N in magnitude .Force always ahorizontally and always 30 N in magnitude. For

always acts tangentially to the track and ismagnitude 15 N. correct magnitude of work don

Are


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(a) W1= W2 =W3 = 120 J

(b) W1=169.6 J ,W2 =180 J , W3 = 141.3 J

(c) W1=140 J , W2 =160 J , W3 = 180 J

(d)W1=120 J , W2 =180 J , W3 = 141.3 J

49. In given figure masses 2m and m released from

rest at same height 50 m from the surface (string

and pulley are mass less & no any friction in it )

After 2 sec the velocity of mass m is

and

velocity of mass 2m is . Find out the total workdone by gravity in 2 second on this system is(a)

(b)

(c)

(d) Zero

50. In given figure lift is moving vertical upwa

with velocity 10 m/s. In this lift incline plane

length S and horizontal base x is placed fix

w.r.t. lift. Object of mass m released at point A

inclined plane. It moved through the inclin

plane & then after travel distance d on horizon

surface before come to rest. Find out the to

work done by friction in its motion ( coefficient

friction of inclined is and horizontal surface

(a) ( + ) ( + )(b) {( ) + }(c) { + }(d)

m 2m

100 m 100 m

50 m

CP

B

A

d x

S

10mLift

1

2

P2

P1

6m

6m

F3

F2

F

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