1.Why is it
desired to hold a gun tight to one’s shoulder when it is being fired?
2. Why does a
swimmer push the water backwards?
3. Friction is a
self adjusting force. Justify.
4. A force is being
applied on a body but it causes no acceleration. What possibilities may be
considered to explain the observation?
5. Force of 16N
and 12N are acting on a mass of 200kg in mutually perpendicular directions.
Find the magnitude of the acceleration produced?
6. An elevator
weighs 3000kg. What is its acceleration when the in the tension supporting
cable is 33000N. Given that g = 9.8m/s2.
7. Write two
consequences of Newton’s second law of motion?
8. How is
centripetal force provided in case of the following?
(i) Motion of planet around the
sun,
(ii) Motion of moon around the
earth.
(iii) Motion of an electron
around the nucleus in an atom.
9. State Newton’s
second, law of motion. Express it mathematically and hence obtain
a relation between force and
acceleration.
10. A railway car
of mass 20 tonnes moves with an initial speed of 54km/hr. On
applying brakes, a constant
negative acceleration of 0.3m/s2 is produced.
(i) What is the breaking force
acting on the car?
(ii) In what time it will stop?
(iii)
What distance will be covered by the car before if finally stops?
11.Draw
a graph showing static , limiting and kinetic friction ?
12.
Define Light year and Astronomical unit with its numerical values.
13.
Define power with its SI unit.
14.
Two bodies A and B having masses 5 kg and 6 kg respectively, have there equal
kinetic energy. Find ratio of their
momentum.
15.
Explain Surface tension , with its one example.
16.
The pressure P=F/A, where F =100 ± 5 pascal and A =10 ± 0.2 m2.Find the percentage
error in P.
17.
Newton’s Second law of motion is the
real law of motion , Explain.
18.State
and prove work energy theorm.
19. Derive the equation by
calculus method
V2-u2=2as
Where symbol has their usual meanings
20. What do you mean by
banking of road and derive the expression for the optimum velocity.
(a)State and prove triangles
law of vectors addition.
(b)The
v – t graph for two bodies in motion is as shown. Which body has more
acceleration
21. Having seen a big stone
falling from the top of a tower Ravi pulled his friend Kiran away. The stone
hit Ravi slightly and he got hurt. But he was saved from a major accident.
(a)What made Ravi act in such a way. (b)From the top of a tower 100 m in
height, a ball is dropped and at the same time another ball is projected
vertically upwards from the ground with a velocity of 25 m/s.Find when and
where the two balls meet. Take g = 9.8 m/sec2.(Value Based Question)
22. In which motion linear
momentum changes but K.E does not?
23. What is the S.I unit and
dimensional formula for plancks constant?
towards each other. Why?
24.
When air is blown between two balls suspended closed to each other. They are
attracted
25.
Write the number of significant figures in (a) 2.64 × 1024 kg (b) 0.00786 g/cm3
26.
Show that impulse of a force is equal to change in linear momentum produced by
the force.
27.State
Newton’s second law of motion on its basis derived the relation between force
and acceleration.
28.
why is it easier to pull than to push a body ?
29.
Write the dimension of aXb in the relation.
F=ax + bt2, where F is force, x is
distance and t is time.
30.
A particle is projected with velocity u making an angle with the horizontal
direction. Write formula for:
(a)
Time of Flight
(b)
Horizontal Range
31. Two bodies A and B having
masses 5 kg and 6 kg respectively, have there equal momentum. Find ratio
of their Kinetic energies.
32. What do you mean by
bending of cyclist and derive the expression for the angle of bending.
33. A truck and car moving
with same K.E are stooped by applying same retarding force by means of breakers
which will stop at a small distance?
34.Define elastic collision.
Prove that bodies of identical masses exchange their velocities s after head on
collision.
35. define centripetal
acceleration. Derive an expression for the centripetal acceleration of a body
moving with uniform speed v along a circular path of radius r.
36.In projectile, a particle
is projected such that magnitude of velocity at topmost point is half of the
magnitude of initial velocity. Find the angle of projectile.
37.State and Prove law of
parallelogram.
38.A projective can have the
same Range R for two angles of projection. If t1 and t2 be the time of flight
in the two cases then prove that:
T1T2=2R/g
39. State and prove law of conservation of linear
momentum.
40. A machine has a mass of
20kg. It fires 35gm bullets at the rate of 4 bullets per second , with the
speed of 400 m sec-1.what force must be applied to the gun to keep it in position
?
41.
Write the laws of limiting friction.Show the angle of friction is numerically
equal to angle of repose
42. A bus moving with a speed
of 36 km hr-1 negotiates a level circular road of radius 10 m .What should be
the coefficient of friction so that the bus may not skit of the road?
43. If the Kinetic Energy of a body increases by 300%, by what
% will the linear momentum of the body increase?
44.
The resistance R=V/I, where V =100 ± 5 V and I =10 ± 0.2 A.Find the percentage
error in R.
45.Suraj
went to Big Bazaar to purchase certain goods .There he has noticed an old lady
struggling with her shopping. Immediately he showed her the lift and explained
to her how it carries the load from one floor to the next. Even then the Old
lady was not convinced.. Then suraj took her in the lift and showed her how to
operate it.. That old lady was very happy. (a)What values does Suraj possess?
(b)An elevator can carry a maximum load of 1800 kg is moving up with a constant
speed of 2 m/s , The frictional force opposing the motion is 4000 N. Determine
the minimum power delivered by the motor to the elevator in watts as well as in
horse power. (Value Based Question)
47.
Rakesh with the intention to win in the interschool sports practiced high jump
every day for about a month. He participated and won I position in the
interschool sports. (a) Comment upon the values Rakesh possesses. (b) Why does
an athlete run some steps before taking a jump? (Value
Based Question)
48 Find the scalar product
between vectors A=3i - 2j + 4k and B = 2i - 4j + 3k.
49. A monkey is sitting on a
tree. Rahim seeing the Monkey brought some fruits
and gave them to the Monkey,
and ran into the house immediately. On hearing the
sound produced when Rahim was
running the monkey was scared and climbed the
nearby tree.
(a) What values of Rahim
inspired you?
(b)A monkey of mass 40 Kg
climbs on a rope which can stand a maximum tension of 600 N .
In which of the following cases
will the rope will break. The monkey
(I) Climbs up with an
acceleration of 6 m/s2
(II) Climbs down with an
acceleration of 4 m/s2
(III) Climbs up with a uniform
speed of 5 m/s
(IV) Falls down the rope nearly
under gravity?
(Take g= 10 m/s2) (Ignore the
mass of the rope) (Value Based Question)
50. A bullet of mass
0.04 kg moving with a speed of 90 m s-1 enters a heavy wooden block
and is stopped after a distance of 60 cm. What is the average resistive force
exerted by the block on the bullet?
51.. The motion of a
particle of mass m is described by y = ut + 1/2 gt2
Find the force acting on the particle.
52. A batsman hits
back a ball straight in the direction of the bowler without changing its
initial speed of 12 m s–1. If the mass of the ball is 0.15 kg, determine the
impulse imparted to the ball. (Assume linear motion of the ball)
53. A circular
racetrack of radius 300 m is banked at an angle of 15°. If the coefficient of
friction between the wheels of a race-car and the road is 0.2, what is the (a)
optimum speed of the racecar to avoid wear and tear on its tyres, and (b)
maximum permissible speed to avoid slipping ?
54. A cyclist
speeding at 18 km/h on a level road takes a sharp circular turn of radius 3 m
without reducing the speed. The co-efficient of static friction between the
tyres and the road is 0.1. Will the cyclist slip while taking the turn ?
55. A wooden block
of mass 2 kg rests on a soft horizontal floor. When an iron cylinder of mass 25
kg is placed on top of the block, the floor yields steadily and the block and
the cylinder
together go down with an
acceleration of 0.1 m s–2. What is the action of the block on the floor (a)
before and (b) after the floor yields ? Take g = 10 m s–2. Identify the
action-reaction pairs in the problem.
56. The driver of
a three-wheeler moving with a speed of 36 km/h sees a child standing in the
middle of the road and brings his vehicle to rest in 4.0 s just in time to save
the child. What is the average retarding force on the vehicle ? The mass of the
three-wheeler is 400 kg and the mass of the driver is 65 kg.
57. A bob of mass
0.1 kg hung from the ceiling of a room by a string 2 m long is set into
oscillation. The speed of the bob at its mean position is 1 m s-1. What is the
trajectory of the bob if the string is cut when the bob is (a) at one of its
extreme positions, (b) at its mean position.
58. A man of mass
70 kg stands on a weighing scale in a lift which is moving
(a) upwards with a uniform speed
of 10 m s-1,
(b) downwards with a uniform
acceleration of 5 m s-2,
(c) upwards with a uniform acceleration
of 5 m s-2.
What would be the readings on the
scale in each case?
(d) What would be the reading if
the lift mechanism failed and it hurtled down freely under gravity ?
59. Two masses 8 kg
and 12 kg are connected at the two ends of a light inextensible string that
goes over a frictionless pulley. Find the acceleration of the masses, and the
tension in the string when the masses are released.
60. A shell of mass 0.020 kg is fired
by a gun of mass 100 kg. If the muzzle speed of the
shell is 80 m s-1, what is the
recoil speed of the gun ?
61. A batsman
deflects a ball by an angle of 45° without changing its initial speed which is
equal to 54 km/h. What is the
impulse imparted to the ball ? (Mass of the ball is 0.15 kg.)
62. A stone of mass
0.25 kg tied to the end of a string is whirled round in a circle of radius 1.5
m with a speed of 40 rev./min in a horizontal plane. What is the tension in the
string ? What is the maximum speed with which the stone can be whirled around
if the string can withstand a maximum tension of 200 N ?
63. Explain why
(a) a horse cannot pull a cart
and run in empty space,
(b) passengers are thrown forward
from their seats when a speeding bus stops
suddenly,
(c) it is easier to pull a lawn
mower than to push it,
(d)
a cricketer moves his hands backwards while holding a catch.
64. A helicopter of
mass 1000 kg rises with a vertical acceleration of 15 m s-2. The
crew
and the passengers weigh 300 kg.
Give the magnitude and direction of the
(a) force on the floor by the
crew and passengers,
(b) action of the rotor of the
helicopter on the surrounding air,
(c)
force on the helicopter due to the surrounding air.
65. A train runs along an unbanked
circular track of radius 30 m at a speed of 54 km/h.
The mass of the train is 106 kg.
What provides the centripetal force required for this
purpose — The engine or the rails
? What is the angle of banking required to prevent
wearing
out of the rail ?
66. A monkey of
mass 40 kg climbs on a rope (Fig. 5.20) which can stand a maximum tension of 600
N. In which of the following cases will the rope break: the monkey
(a) climbs up with an
acceleration of 6 m s-2
(b) climbs down with an
acceleration of 4 m s-2
(c) climbs up with a uniform
speed of 5 m s-1
(d)
falls down the rope nearly freely under gravity?
67. A block of mass
15 kg is placed on a long trolley. The coefficient of static friction between
the block and the trolley is 0.18. The trolley accelerates from rest with 0.5 m
s-2 for 20 s and then moves with uniform velocity. Discuss the
motion of the block as viewed by (a) a stationary observer on the ground, (b)
an observer moving with the trolley.
68. The rear side of a truck is open
and a box of 40 kg mass is placed 5 m away from the open end as shown in Fig
The coefficient of friction between the box and the surface below it is 0.15.
On a straight road, the truck starts from rest and accelerates with 2 m s-2.
At what distance from the starting point does the box fall off the truck?
(Ignore the size of the box)
69.
Ten one-rupee coins are put on top of each other on a table. Each coin has a
mass m.
Give the magnitude and direction
of
(a) the force on the 7th coin
(counted from the bottom) due to all the coins on its top,
(b) the force on the 7th coin by
the eighth coin,
(c)
the reaction of the 6th coin on the 7th coin.
70. A stone of mass
0.25 kg tied to the end of a string is whirled round in a circle of radius 1.5
m with a speed of 40 rev./min in a horizontal plane. What is the tension in the
string ? What is the maximum speed with which the stone can be whirled around
if the string can withstand a maximum tension of 200 N ?
71. Radha found the
wheel getting detached from her uncle’s car . She took it to workshop and got
it repaired. She informed her uncle, who is a mechanical engineer, about this
matter. (a) What according to you the values displayed by Radha? (b)A thin
wheel can stay up-right on its rim for a considerable length of time when
rolled with a considerable velocity, while it falls from its upright position
at the slightest disturbance, when stationery. Explain. (
Value Based Question)
72. Suresh noticed
a big Granite Rock in his locality. He thought that if they worked upon it they
could earn money. He took permission from the Government, completed all the
formalities .He broke the Rock using a bomb. The rock was made into slices
.They established a Granite industry. Many of the people in the surroundings
started to earn and live comfortably. (a) What values of Suresh impress you?
(b)A bomb is thrown in a horizontal direction with a velocity of 50 m/s. It
explodes into two parts of masses 6 Kg and 3 Kg. the heavier fragment continues
to move in the horizontal direction with a velocity of 80 m/s .Calculate the velocity
of the lighter fragment. .
( Value Based
Question)
73. A 2 kg ball on
a string is rotated about a circle of radius 10 m. The maximum tension allowed
in the string is 50 N. What is the maximum speed of the ball?
74. A satellite is
said to be in geosynchronous orbit if it rotates around the earth once every
day. For the earth, all satellites in geosynchronous orbit must rotate at a
distance of 4.23×107 meters from the earth's
center. What is the magnitude of the acceleration felt by a geosynchronous
satellite?
75.The maximum lift
provided by a 500 kg airplane is 10000 N. If the plane travels at 100 m/s, what
is its shortest possible turning radius?
76.Prove that the
angular projectile form parabolic path , derive expression for time of flight ,
range and height of projectile.
77.Prove the
relation between linear speed and angular velocity V = r ω
78. A machine has a mass of
20kg. It fires 35gm bullets at the rate of 4 bullets per second , with the
speed of 400 m sec-1.what force must be applied to the gun to keep
it in position ?
79.Derive the expression Snth
= u + a/2(2n-1)
Physics Classes By Er.Shyam Pachori add: C.L 81 D.D Nagar Mob.: 9039803981 Batches TTS / MWF Time: 5 - 7 Pm
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