C:\PHYSICS-2\YEAR-P2-2005-2006\BANK\QUIZES-05\MASTER BANKS||5/11/2012||V4
WEP-MASTER-BANK LEVEL - I 1.
A particle falls from rest under gravity. Its potential energy with respect to ground (P.E) and its kinetic energy (K.E.) are plotted against time t. Choose the correct graph. (A) (B) (C) (D)
PE
KE
KE
PE KE
PE
KE t
t
PE t
t
2.
A ball of mass 0.1 kg is dropped from a height of 10 m. What is the kinetic energy of the ball when it hits the ground ? (A) 25 J (B) 10 J (C) 15 J (D) 30 j
3.
What is the shape of the graph between the speed and kinetic energy of a body ? (A) straight line (B) hyperbola (C) Parabola (D) Exponential
4.
Work done by weight of car, which moves with a uniform speed on road is________
5.
Work done by force 100 N which makes 60o with horizontal moves 50 kg block through a horizontal distance of 10 m. (A) 500 J (B) 1000 J (C) 200 J (D) 900 J
6.
Spring constant of spring which has potential energy of 50 J when it is stretched through a distance of 10 cm is (A) 112 × 102 N/m (B) 100 × 102 N/m (C) 900 × 102 N/m (D) 70 × 103 N/m
7.
Amount of work done by a man pressing a rigid wall with a force of 200 N is ______
8.
Two inclined frictionless tracks, one gradual and other steep meet at A from where two stones are allowed to slide down from rest, one on each track. The stones reach at bottom with different speed (sate true or false).
1
A 2 h θ2
θ1 B
C
9.
At any instant force of 10 N, acting on body moving with 4 m/s. Power is ________.
10.
Work done by gravity in lifting water (10 kg) from well to height of 10 m is _______. (Assume g = 10m/s2)
11.
A weight lifter lifts 300 kg from ground to a height of 2 m in 3s. The average power generated by him is (A) 5880 Watt (B) 1960 Watt (C) 9000 Watt (D) 200 Watt
12.
Friction is a conservative force, while Potential Energy is non conservative (Sate true or false).
13.
Work done in holding a mass of 50 kg at a height of 1m above ground is (A) zero (B) 25 J (C) 100 J
(D) 980 J
14.
The earth moving round the sun in a circular orbit is acted by a force and hence work must be done on the earth by this force. Do your agree with the statement. (A) True (B) False
15.
Scalar product of force with displacement is called (A) work (B) power (C) energy
(D) Momentum
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1 th of its velocity in passing through a plank. The least number of such planks 20 required just to stop the bullet is (A) 5 (B) 10 (C) 11 (D) 20
16.
A rifle bullet loses
17.
Two springs A and B are identical except that A is stiffer than B, i.e. force constant KA > KB. In which of the springs more work is expended, if they are stretched by same amount then (A) WA > WB (B) WB > WA (C) WA = WB (D) can not be decided
18.
In the above question, in which of the springs more work is extended, if they are stretched by the same force (A) WA > WB (B) WB > WA (C) WA = WB (D) can not be decided
19.
Can a body have energy without having momentum (A) the body which has no momentum will have no energy (B) the body which has no momentum, will have potential energy by virtue of its position. (C) the body which has no momentum, will have no kinetic as well as potential energy. (D) nothing can be said
20.
A particle of mass m has momentum P. Its kinetic energy is (A) mp (B) p2m (C) p2/m
(D) p2/2m
Newton-metre is the unit of (A) Force (B) Work
(D) Both (B) and (C)
21. 22.
(C) Moment of force
When a ball is thrown up, the magnitude of its momentum decreases and then increases. Does this violate the conservation of momentum (a) the conservation of momentum is violated (b) the conservation of momentum is not violated. Here the system includes (ball + earth + air molecules) and the net momentum of the system remains constant.
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[
LEVEL - II 1.
2.
X
Y
A block X slides down upon a friction less inclined plane when released from the top of the inclined plane while another block h h falls freely from the same point then θ (A) block X will strike the ground first (B) block Y will strike the ground first (C) both block will strike the ground simultaneously. (D) none. A car of mass m is driven with acceleration 'a' along straight level road against constant external resistance R. When the velocity is v, the rate at which the engine is working is, (A) Rv (B) m.av (C) (R + ma).v (D) (R - ma)v (E) (ma - R).v
3.
A uniform chain of length L and mass M is lying on a smooth table and one-third 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 the table is MgL MgL MgL (A) MgL (B) (C) (D) 3 3 18
4.
A body is moved along a straight line by a machine delivering constant power. The distance moved by the body in time t is proportional to: (A) t1/2 (B) t3/4 (C) t3/2 (D) t2
5.
A body of mass 1 kg and momentum 2 Ns has kinetic energy equal to (A) 3J (B) 5J (C) 2J
(D) 8J
6.
A body moves a distance of 10m along a straight line under the action of a 5N force. If the work done is 25 J, then angle between the force and the direction of motion of the body is (A) 30° (B) 45° (C) 60° (D) 75°
7.
A 10 kg mass rests on a horizontal frictionless table. How much energy is needed to accelerate the mass from rest to a speed of 5 m/s (A) 125 J (B) 150 J (C) 175 J (D) 200 J
8.
The potential energy of a spring when stretched through a distance S is 10 J. The amount of work (in Joules) that must be done on this spring to stretch it through an additional distance S will be (A) 30 J (B) 40 J (C) 10 J (D) 20 J
9.
A long spring is stretched by 2 cm, its potential energy is V. If the spring is stretched by 10 cm, the potential energy stored in it will be V V (A) (B) (C) 5 V (D) 25 V 25 5
10.
A block of mass 2 kg is moved on a frictional horizontal plane by applying horizontal force of 10 N. The coefficient of friction is 0.2. The kinetic energy of block, after it has moved a distance of 10 m, is (A) 100 J (B) 40 J (C) 20 J (D) 60 J
11.
An engine pumps up 100 kg of water through a height of 10 m in 5 second. Given that the efficiency of engine is 60 %. The power developed by the engine is (A) 33 kW (B) 3.3 kW (C) 0.33 kW (D) 0.33 kW
12.
A uniform chain of mass ‘m’ and length is held on a horizontal frictionless table with
1 th of its length n hanging over the edge of the table. The wok done in pulling the chain up on the table is mgl mgl mgl mgl (A) (B) (C) 2 (D) n 2n n 2n2
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13.
A ship of mass 3 × 107 kg initially at rest is pulled by a force of 5 × 104 N through a distance of 3m. Assume that the resistance due to water is negligible. The speed of the ship is (A) 1.5 m/s (B) 60 m/s (C) 0.1 m/s (D) none of these
14.
A mass of 900 gm is kept on a vertical spring. What is the compression of the spring? (spring constant is 300 N/m) (A) 3m (B) 30 mm (C) 6 mm (D) 20 mm
15.
An engine pump is used to pump a liquid of density ρ continuously through a pipe of cross-sectional area A. If the speed of flow of the liquid in the pipe is v, then the rate at which kinetic energy imparted to the liquid is 1 1 1 (A) ρAv 3 (B) ρAv 2 (C) ρAv (D) ρAv 2 2 2
16.
If momentum of a body is increased by 20 %, then kinetic energy increases by (A) 44 % (B) 55 % (C) 66 % (D) 77 5
17.
A bullet is fired normally on a immovable wooden plank. It loses 25 % of its kinetic energy in penetrating a thickness x of the plank. What is the total thickness penetrated by the bullet ? (A) 2x (B) 4x (C) 6 x (D) 5x
18.
A wind power generator converts wind energy into electrical energy. Assume that the generator converts a fixed fraction of the wind energy. For wind speed v, the electrical power output will be proportional to (A) v (B) v2 (C) v3 (D) v4
19.
A ball is thrown up with a certain velocity at an angle θ to the horizontal. The variation of its kinetic energy K.E. with respect to the horizontal displacement 'X' from the point of projection is best represented by : (A) (B) (C) (D) K.E.
K.E.
v
20.
21.
K.E.
v
K.E.
v
v
r If a particle changes its position from (2m, 2m) to (4m, 4m) while the force F −10ˆj N is acting on it, r work done by the force F would be (A) – 20J (B) 20J (C) 40J (D) 0J
(
Consider a body of mass (m) is moving on the frictionless surface as shown below. The velocity at bottom of surface i.e. at B is ________.
A
)
m
h B
22.
A particle moves under effect of a force F = cx from x = 0, to x = x1 . The work done on forces is 1 (A) Cx12 (B) Cx12 (C) Cx13 (D) zero 2
23.
A body of mass 2.0 kg is at rest at height of 10 m above the ground. Calculate its P.E. and K.E. after it has fallen through half the height (A) 98 J, 98 J (B) 110 J, 120 J (C) 20 J, 40 J (D) 90 J, 30 J
WEP-master-bank 24.
The below given graph shows the force variation of spring force of a spring with stretching of spring. The change in potential energy is _______.
WEP-5
F(x) = Kx x
25.
If the force acting on a body is inversely proportional to its speed then K.E. of the body is (A) constant (B) directly proportional to time (C) inversely proportional to time (D) directly proportional to square of time
26.
A cricket ball is hit at an angle θ to the horizontal with a kinetic energy of k. The KE at highest point is (A) zero (B) Kcosθ (C) Kcos2θ (D) Ksec2
27.
The work done by external forces on a body equals the change in (A) KE only (B) PE only (C) Thermal energy only (D) Total energy
28.
A position dependent force F = 7 - 2x + 3x 2 N, acts on a small body of mass 2 kg and displaces it from x = 0 to x = 5m. The work done in Joules is (A) 35 (B) 40 (C) 135 (D) 270
29.
If a light body A and a heavy body B have the same kinetic energy then ratio of the momentum of A to that of B (A) =1 (B) >1 (C) <1 (D) can not be calculated
30.
A ball of mass m is moving with speed u hits a wall of mass M (>> m) moving with speed v directly towards the ball. If impact is elastic then work done on the ball by the wall is ________.
31.
The end of a pile of loose-link chain of mass per unit length f is being pulled horizontally along the surface by a constant force F. If the co-efficient of kinetic friction between the surface and the chain is , then acceleration of the chain when length x is pulled will be _______.
32.
A small ball of mass m is released from rest from height 2h to slide on smooth track which turns in a vertical of radius h. At the highest point speed of the ball will be _________.
x
h 2h
33.
How much work is done in raising a stone of mass 5 Kg and relative density 3 lying at the bed of a lake through height of 3 metre? (Take g = 10 ms-2): (A) 25 J (B) 100 J (C) 75 J (D) None of the above
34.
The equal retarding force is applied to stop a train. If the speed is doubled then the distance covered before being stopped will be (A) the same (B) doubled (C) half (D) four times
35.
A ball is allowed to fall from a height of 10 m. If there is 40 % loss of energy due to impact, then after one impact the ball will go upto (A) 10 m (B) 8 m (C) 4 m (D) 6 m
36.
r Work done when a force F = ( ˆi + 2 ˆj + 3 kˆ ) N is acting on a particle to take it from the point r1 = ( ˆi + ˆj r + kˆ ) m and r2 = ( ˆi −ˆj + 2 kˆ )m is (A) − 3J
37.
(B) − 1 J
(C) Zero
(D) 2 J
Two bodies of masses m1 and m2 have equal momentum. Their kinetic energy E1 and E2 are in the ratio 2 2 (A) √m1 : √m2 (B) m1 : m2 (C) m2 : m1 (D) m1 : m2
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a b − where a and b are x12 x 6 positive constants and x is the distance between the atoms. The atom is in stable equilibrium when (A) x = 6 11a /(5b) (B) x = 6 a /(2b) (C) x = 0 (D) 6 2a / b
38.
The potential energy between two atoms in a molecule is given by U(x) =
39.
One meter stick having mass 600 gm, is pivoted at one end. And is displaced through an angle of 60°, the increase in its potential energy is (g = 10 m/s2) (A) 1.5 J (B) 15 J (C) 150 J (D) 0.15 J
40.
A block of mass M is lowered vertically by a cord through a distance d with constant acceleration g/4. The work done by cord on the block is mgd mgd (A) (B) − (C) mgd (D) none of these. 4 4
41.
A light elastic cord of natural length OA is suspended from O. A load of mass 'm' is attached to A and released from the undeformed state of the cord. The mass oscillates vertically between A and B AB being equal to h. When the mass is at B, the potential energy stored in the cord is (A) mgh
(B) mg
h 2
(C) 2mgh
(D)
60°
mgh 2
42.
When work is done ________ a ________ force on a body, the potential energy of the body by conservative decreases.
43.
A solid sphere rolls down a parabolic path, whose vertical dimension y = kx2 and base of the parabola is at x = 0. During the fall, the sphere does not slip, but beyond the base the climb is frictionless. If the sphere falls a height h , the height above base that it would climb equals (A) h (B) (7/5)h (C) (5/7)h (D) none of these
44.
The kinetic energy of a body moving with a speed of 10 m/s is 30 J. if its speed becomes 30 m/s its kinetic energy will be (A) 10 J (B) 90 J (C) 180 J (D) 270 J
45.
When a body of mass M slides down an inclined plane of inclination θ, through a distance s, the work done by surface is: (µ is coefficient of friction) (A) µ Mg cos θ s (B) µ Mg sin θ s (C) Mg (µ cos θ- sin θ)s (D) None of the above
46.
If v, P and E denote the velocity, momentum and kinetic energy of the particle, then: (A) P = dE/dv (B) P = dE/dt (C) P = dv/dt (D) none of these
47.
In the spring mass system shown in the figure, the spring is compressed by x0 = mg/3k from its natural length and the block is released from rest. The speed of the block , when it passes through the point P, is (A) g
48.
m k
(B) g
2m 9k
(C) g
m 3k
x0 k
m
k
P
3m 2k
(D) g
r r An object is acted upon by the forces F1 = 4iˆ N and F2 = (iˆ − ˆj) N. If the displacement of the object is ( r r r i + 6 j − 6k ) metre, the kinetic energy of the object (A) remains constant (B) increases by 1 J (C) decreases by 1 J (D) decreases by 2J
49.
When work done by force of gravity is negative, which of the following will definitely occur (A) Potential energy increases. (B) Kinetic energy decreases. (C) Gravitational Potential energy increases. (D) Gravitational Potential energy decreases.
50.
A rod is allowed to fall down on the floor from vertical position. There is sufficient friction to prevent slipping at the end of the rod on the floor which of the following principle are applicable (A) conservation of energy (B) conservation of angular momentum
y
θ
WEP-master-bank (C) conservation of linear momentum 51.
52.
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(D) none of these
r r A point of application of a force F = 5iˆ − 3ˆj + 2kˆ is moved from r1 = 2iˆ + 7ˆj + 4kˆ to r2 = −5iˆ + 2ˆj + 3kˆ . The work done is (A) –22 units (B) 22 units (C) 11 units (D) zero A body of mass ‘m’ is connected to two springs of spring constants K1 and K2 and is in equilibrium on a smooth horizontal surface as shown. If the body is displaced to the left by a small distance ‘x’ from the position shown, what is the velocity of the body as its passes this position again? (springs are massless) K + K2 (A) 0 (B) x 1 (C) (K1 + K2)x m
k
x0 m
k
P
(D) data insufficient
53.
A lorry and a car moving with the same K.E. are brought to rest by the application of brakes which provide equal retarding force. Which of them will come to rest in a shorter distance (A) lorry will move shorter distance before coming to rest (B) car will move shorter distance before coming to rest (C) both will move same distance before coming to rest (D) can not be decided, since mass of the lorry or the car is not given.
54.
Work done in time t on a body of mass m which is accelerated from rest to a speed v in time t1 as a function of time t is given by 1 v 2 (A) m t 2 t1
55.
56.
(B) m
v 2 t t1
2
1 mv 2 (C) t 2 t1
(D)
A block of mass m is released on the frictionless incline as shown from a height R. The incline turns in to a circle of radius R/2. The maximum height attained by the block is (A) less than R/2 (B) greater than R/2 (C) equal to R (D) less than R
1 v2 2 m t 2 t12
R
R/2
A body of mass m is falling freely through a height h from the top of a tower. The velocity just before touching the ground is (3 / 2)gh . The work done by air drag is (A) −
mgh 4
(B) +
mgh 4
(C) Zero
(D) None of the above
57.
A block of mass 5 kg is allowed to slide on a frictionless wedge, free to move on a horizontal smooth surface. The 10 m increase in gravitational potential energy of block and wedge, 370 when block reaches the bottom, is (A) 500 J (B) 400 J (C) 300 J (D) none of the above
58.
From a waterfall, is pouring down at the rate of 100kg per second on the blades of the turbine. If the height of the fall be 100m, the power delivered to the turbine is (A) 100KW (B) 10KW (C) 1 KW (D) 100W
59.
60.
r ˆ where k is a positive constant acts on a particle moving in the x-y plane. A force F = −k(yiˆ + xj) Starting form the origin, the particle is taken along positive x-axis to the point (a, 0) and then parallel r to the y-axis to the point (a, a). The total work done by the force F on the particle is (A) -2ka2 (B) 2ka2 (C) –ka2 (D) ka2 r A particle move in X- Y plane under the influence of a force F such that its instantaneous momentum r is P = (2cos t)iˆ + (2sin t)jˆ . What is the angle between the force and instantaneous momentum? (A) 00C (B) 1800 (C) 900 (D) 450
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61.
A conservative force field is that field in which work done against _________ in transporting a test body along ________ equals ________.
62.
A heavy particle is projected up from a point at angle with the horizontal. At any instant 't', if P = linear momentum, y = vertical displacement, x = horizontal displacement, then the kinetic energy of the particle plotted against these parameters can be (A) (B) (C) (D) KE
KE O
63.
v
KE
KE O
t
O
y
The plot of velocity versus time is shown in the figure. A varying force acts on the body. The correct statement(s) among the following is (are) (A) in moving from A to B, work done on the body is negative. (B) in moving from B to C no work is done on the body.
O
ν
A
B
p2
C D t E
(C) in moving from C to D, work done by the force on the body is positive. (D) in moving from D to E, work done by the force on body is positive.
LEVEL – III 1.
A particle of mass m is projected with velocity u at an angle θ with horizontal . During the period when the particle descends from highest point to the position where its velocity vector makes an angle θ/2 with horizontal, work done by the gravity force is 1 1 1 1 (A) mu2 tan2 θ/2 (B) mu2 tan2 θ (C) mu2 cos2 θ tan2θ/2 (D) mu2 cos2 θ/2 sin2θ 2 2 2 2
2.
A uniform chain of mass M and length L lies on a frictionless table with length 0 hanging over the edge. The chain beings to slide down. Then the speed with which the end slides away form the edge is given by g g g 2 g 2 (A) v = (B) v = (C) v = (D) v = (L + l 0 ) (L − l 0 ) (L − l 20 ) (L + l 20 ) L L L L
3.
A particle of mass m is moving in a circular path of constant radius r such that its centripetal acceleration ac is varying with time t as ac = K2.r.t2, where k is a constant. The power delivered to the particle by the forces acting on it is (A) 2π mK2.r2.t (B) mK2.r2t (C) mK4.r2.t5/3 (D) zero
4.
The relation between the displacement x and the time t for a body of mass 2 kg moving under the t3 action of a force is given by x = , where x is in meters and t is in seconds. The work done by the 3 body in the Ist 2 seconds is (A) 1.6 J (B) 16 J (C) 160 J (D) 1600 J
5.
A block is attached to a horizontal spring of stiffness k. The other end of the spring is attached to a fixed wall. The entire system lie on a horizontal surface and the spring is in natural state. The natural 5 length of the spring is 0. If the block is slowly lifted up vertically to a height 0 from its initial 12 position, which of the following is not correct? 5 (A) The work done by the gravity = mg0 12 kl 2 (B) The work done by the spring force = − 0 288
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kl 2 5 mgl 0 + 0 12 288 (D) The sum of works done by all the forces on the block is zero. (C) The work done by the lifting force =
6.
A bullet of mass 10 gm is fired from a rifle with a velocity of 800 m/s. After passing through a mud wall 180 cm thick, the velocity drops to 100 m/s. The average resistance of the wall is (A) 750 N (B) 1250 N (C) 1750 N (D) 2250 N
7.
A body is gently dropped on a conveyor belt moving 3 m/s. If = 0.5 how far will the body move relative to the belt before coming to rest? (g = 10m/s2) (A) 0.3 m (B) 0.6 m (C) 0.9 m (D) 0.8 m
8.
A ball hits a horizontal surface with speed 10 m/s at an angle of incidence 30 o. If coefficient of 3 restitution is then distance between the point of incidence and the point at which ball hits the 2 plane second time is _____.
9.
A man of mass m is standing on a plank mass M placed on smooth horizontal surface. If the man moves a distance x relative to the plank then distance moved by the centre of mass of the system is _________.
10.
A block of mass M slides along the sides of a flat bottomed bowl. The side of the bowl are frictionless and the base has a coefficient of friction 0.2. If the block is released from the top of the side which is 1.5 m high, where will the block come to rest. Given, the length of the base PQ is 15 m (A) 1 m from P (B) mid point of flat part PQ(C) 2 m from P (D) at Q
11.
A spring is compressed between two toy –carts of masses m1 and m2. When the toy –carts are released, the spring exerts on each toy-cart equal and opposite force for the same time t. If the coefficient of friction ‘µ’ between the ground and the toy-carts are equal, then the displacements of the two toy-carts : 2 2 S1 m S1 m m m S S =− 2 =− 1 (A) (B) (C) 1 = − 2 (D) 1 = − 1 S2 m1 S2 m2 S2 S2 m1 m2
12.
13.
ˆ A force acting on the body is given by F = x2y ˆi + yx2 j , where x and y are coordinates. Then that force is (A) Conservative force (B) Non-Conservative force (C) Can’t say (D) none of these A particle of mass m is moving in a horizontal circle of radius r under a centripetal force equal to − where K is a constant. Then KE of the particle will be K (A) 2 (B) kr (C) 2k/r r
14.
K , r2
(D) k/2r
For a body of mass m moving on a straight line position is given as x = 4t 2 + 3t + 5. Find the work done in 3 to 5 seconds. (A) The change in the kinetic energy of a body must be equal to the sum of the works done by various forces acting on the body. (B) The change in the total energy (kinetic + potential energy) is equal to the sum of works done by various forces acting on the body. (C) Potential energy is defined if and only if the force is such that the net work done on a body on a closed path is zero. (D) If the force acting on a body is dependent on its velocity, then also it is possible to define its potential energy.
WEP-master-bank
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Level - I 1.
D
2.
B
3.
C
4.
zero
5.
A
6
B
7.
zero
8.
false
9.
40 W
10.
−103 J
11
B
12.
false
13.
A
14.
B
15.
A
16.
17.
A
18.
B
19.
B
20.
D
21.
D
22
B
1.
B
2.
C
3.
D
4.
C
5.
C
6
C
7.
A
8.
A
9.
D
10.
D
11
D
12.
D
13.
C
14.
C
15.
A
16.
A
17.
B
18.
B
19.
20.
D
22.
B
23.
A
24.
26.
C
27.
D
28.
31.
µmgh
32.
Level - II
2gh
21. 25. 29.
B
33.
30.
C
34.
D
35.
D
36.
B
D
39.
A
40.
D
43.
A
44.
D
37.
C
38.
41.
A
42.
45.
D
46.
A
47.
B
48.
C
49.
D
50.
A
51.
A
52.
B
53.
C
54.
D
55.
?
56.
?
60.
3.
B
4.
57.
58.
59.
61.
62.
63.
Level – III 1.
C
2.
5.
A
6
C
7.
C
8.
9.
mx M+m
10.
D
11.
B
12.
13.
?
14.
B
