WORKSHEET

STUDENT PRACTICE SHEET

Questions)
CUQ (Conceptual Understanding rests On a horizontal surface C' which is
'B' rests on 'A A
A block If B' is pulled to the right
1.
frictionless. There is friction between A and B.
1. B moves foward and A to the left
2. B' only mOves to the left
3. B'does not move
4. 'A' and B'move together to the right
distance on a horizontal road, one should
In order to stop acar in shortest
1. apply the brakes very hard so that the wheels stop rotating
2. apply the brakes hard enough to just prevent slipping
3. pump the brakes (press and release)
4. shut the engine off and not apply brakes
In which of the following cases Frictional Force is Greatest?
1) Smooth surface block sliding on the Rough surface
2) Rough surface block sliding on the Rough surface
3) Smooth surface block sliding on the Smooth surface
4) Rough surface block sliding on the Smooth surface
The Self Adjusting Force' means
1) Frictional Force is greater than the Applied Force
2) Frictional Force is less than the Applied Force
3) Frictional Force is equal to the Applied Force
4) Frictional Force is either greater than or less than the Applied Force
Two cars of unequal masses use similar tyres. If they are moving at the same
initial speed, the minimum stopping distance.
1) is smaller for the heavier car 2) is smaller for the lighter car
) is same for both cars 4) depends on the volume of the car
na situation the contact force by a rought horizontal surface on a body placed on
has constant magnitude. If the angle between this force and the vertical is
creased, the friçitional force between the surface and the body will
Increase 2) decrease
remain the same 4) may increase or decrease

cOPROGR CO -SPARK 11
 7

0)92V45
 mal ne eiM between wo srfaces

) Nehams te

ntotion
3) Same as that ot tuetL ot

a force of SN. The

weighting N tn eNed agaiHat he laktoard with
An eraNer
won N(04 Hw hfove atallel to the black board is required
coeticient ot
to slide he etase uwaa ) 4.8N
)N
) 2N
depend
The initing iwion btween (wo autaves toes not
)on tormal reaction
) on the naure o (wo Nurfaces
4) on volume of the body
3) on the weght ofhe bodv
car noving withdisengaged engine, bringing it to a
8. Brakes are applied to a breaks are applied if the
halt after velocity at the omeut when the
2s. lts
the toad and the tyres is 0.4 is
coefficient of ieion between
4) 19,6 ms
) 7.8-4 ms! 3) L2ms
1) 3.92 ms
riction is
9, Maximum value of static 3) statie friction 4) normal reaction
) Limiting friction 2) rolling riction triction exerted by the ground on tl
is in motion, the force of
0, When abicycle
two wheels is such that it acts
direetion on the front wheel and in the forward direction
Hin the backward
the rear wheel
direction on the front wheel and in the backward direction
2) in the forward
the rear wheel
backwvard direction on both the front and rear wheels
3) in the and rear wheels
both the front
4) in the forward direction on
Scm x 8emx 15em has to be pushed along the floor.
21. An iron block of sides the surtuce in contact with the grour
will be minimum when
force required
15 cm surtace
2) S em x 15cnn surface
1) 8 cmn x surfaces
4) force is same for all
3) 8 cn x 5cm surtace
and surface area A just begins to slide dovn an in
?2. Ablock of mass m n/5. Keeping the mass of the
inclination is
plane when the angle of doubled, the inclination of the
plane at wh
same, if the surface area is
block starts sliding will be
2) n/I0 3) 2n/5
n/5

CO-SPARK
 FRICTION
1A
PHYSICs-CLASS - VII
With increase of temperature. the frictional force acting between two surfaces
1) Increases
2) Decreases
3) Remains same
4) May increase or decrease
15 If man is walking. direction of fictton is
1) Opposite to dircction of motion
2) Same as that of direction of
motion
3) Perpendicular to that of
direction of motion
4) 45° to the direction of
motion
16. An eraser weighting 2N is pressed against the
black board with a force of 5N. The
coeficient of friction is 0.4. How much force parallel to the black
to slide the eraser board is required
upwards?
1) 2N 2) 2.8 3) 4N 4) 4.8N
The limiting friction between two
surfaces does not depend
1) on the nature of two
surfaces 2) on normal reaction
3) on the weight of the body 4) on volume of the body
18. Brakes are applied to a car moving with
disengaged
halt after 2s. Its velocity at the moment when the engine, bringing it to a
breaks are applied if the
coefficient of friction between the road and the tyres is 0.4 is
1) 3.92 ms-! 2) 7.84 ms-! 3) 11.2ms-! 4) 19.6 ms-!
9. Maximum value of static friction is
W Limiting friction 2) rolling friction 3) static friction 4) normal reaction
0. When a bicycle is in motion, the force of friction
exerted by the ground on the
two wheels is such that it acts
Hin the backward direction on the front wheel and in the
forward direction on
the rear wheel
2) in the forward direction on the front wheel and in the backward direction on
the rear wheel
3) in the backward direction on both the front and rear wheels
4) in the forward direction on both the front and rear wheels
An iron block of sides 5cm x 8cm x 15cm has to be pushed along the floor. The
force required will be minimum when the surface in contact with the ground is
1) 8 cm x 15 cm surface 2) 5 cm x 15cm surface
3) 8 cm x 5cm surface 4Y force is same for all surfaces
A block of mass m and surface area A just begins to slide down an inclined
plane when the angle of inclination is I/5. Keeping the mass of the block
same, if the surface area is doubled, the inclination of the plane at which the
block starts sliding will be
n/5 2) n/10 3) 2n/5 4) n/5V2

CO-SPARK 13
 PHYSICsCLASS VIl FRICTION
23 When a person walks on a tough surface
) The frictional force cxeted by the surface keeps him stationar.
tracion of the force appied by the man on the surface
3) the force applied by the man kecp him moving keeps hiim mesN A

4) none of the abOve

re

JEE MAIN &ADVANCED 1

Single Correct Answer Type:

Among the following, regarding friction, the invalid statement is
LEVEL A
W

1) Static frictional force can be less than (4). 1

2) Static frictional force may be greater than (4M). 6 A

3) Static frictional force can be equal to (W). be

le
4) Static frictional force will always be equal to (H).
1
A 2.5kg block is initially at rest on a horizontal surface. A horizontal for T
,7.
magnitude 6.0N and a vertical force p are then applied to the block (Figure
coefficients of friction for the block and surface are , =0.40 and u, = 0.25 th
magnitude of the frictional force acting on the block if the magnitude of Bis 1n be
is

8 If
P

l)6N 2)3.6N 3)3.1N 4)2.36N

3 A 50.0-kg crate rests on the bed of a stuck as shown in
figure .The coefficients
friction between the surface are u, =0.300 and u. =0.400.The
frictional force o 10.
the crate when the truck is accelerating forward relative to
the ground
2.00m/s² is

490 N
11.
50 kg

12.

(a)
(

l)100N 2)196N 3)250N 4)147N

CO -SPARK
 FRICTION PHYSIC8- CLASS-VIII
Ahorizontal torce applied on abody on a tough hoizontal surface produes an
wcleation ' Wo etticicnt of feton etween the body surface which is Llis
rrduced to /3, the acceleutiou incrcasca by 2 tùmes. The value ofiis
2) 3a/2H 4) a/g
A body of weight 20N is on a horizontal surface, minimum force applicd to pull it
when aPpied foee makes an angle o'with horizontal (angle of friction ,-30') is
20
1) 2ON 2) 20/3N 3) 7 4) 20N

Aheavy uniform chain lies on horizontal table top. If the co-efficient of friction
between the chain and the table surface is 0.25, the maximum percentage of the
length of the chain that can hang over one edge of the table is
1) 20%o 2) 25% 3) 35% 4) 15%
7. The rear side of truck is open and a box of mass 50kg is placed at 3.2m away frorn
the open end. The co-efficient of friction between the box and the surface is 0.2. If
the truck starts from rest and moves on astraight road with acceleration 2.Imsthe
box falls off the truck after a time (g=10ms)
8
1 2) 4 s 3) 8 s 4) V8s
8. If the Angle of Friction is 45°, then the Coefficient of Static Friction (f) =

1) 1 2) J2 3) 0 4) o

9. The coefficients of static and dynamic friction are 0.7 and 0.4. The minimum
force required to create motion is applied on a body and if it is further continued,
the acceleration attained by the body in ms² is (g = 10m/s)
1) 7 2) 4 3) 3 4) Zero
10. The coefficient .of static friction between contact surfaces of two bodies is 1.
The contact surfaces of one body support the other till the inclination is less
than
1) 30° 2) 45° 3) 60° 4) 90°
11. Abook of weight 20N is pressed between two hands and each hand exerts
force of 40N. If the book just starts to slide down. Coefficient of friction is
1) 0.25 2) 0.2 3) 0.5 4) 0.1
12. Ablock of mass 10kg is on a rough horizontal surface. A horizontal force 4N i
applied on it. If coefficient of static friction between those two surfaces is 0.
frictional force between the two surface in contact is
1)20 N 2) 49 N 3) 4.9 N 4) 4 N

CO -SPARK 15
 oN

tattet atwa

05 ) 0.7

) 5.7 N

I nNN t sQNNbn then stopping time will be

3) rnains Sam 4) tripled

surface is 0.4 then, M:at

TEfCET T I r bewn he block and the
Ta-I
Column - II

2kg
1)

+F=2.5N
2kg
2)

F=5N

3 2kg

F-5N
K60°
4) 2kg

(3NARK
 PHYSIC8- CLASs-VIII
FRICTION
LEVEL-2
JEE MAIN &ADVANCED
Single Correct Answer Type:
The coefficient of static friction is 0,4
Ablock of mass 2kg is placed on the floor
18
parallel to floor the force of friction
If a force of 28Nis applied on the block
betwren the block and floor (taking g-1Om/S') is
2) 8 N 3) 2N 4) Zero
1) 28N
When a bicycle is in peddling. the force of
friction exerted by the ground on the
two wheels is such that it acts
and in the forward direction on
1) In the backward direction on the front wheel
the rear wheel
and in the backward direction on
2) In the forward direction on the front wheel
the rear wheel

3) In the backward direction on both

the front and rear wheels

and rear wheels

4) In the forward direction on both the front
between the
surface. The coefficient of friction
20. A mass m rests on a horizontal
by a force F as shown in Fig. the
mass and the surface is H. If the mass is pulled
surface will be:
limiting fricition between the mass and the

300

1) umg 2) u[mg -(V3 /2)F]

3) u(mg - (F /2)) 4) u[mg + (F /2)]
wall by applying a horizontal force of 5 N
21. A block of mass 0. 1 kg is held against a
on the block. If the coefficient of fricition
between the block and the wall is 0.5.
on the block is
the magnitude of the fricitional force acting
2) 0.98 N 3) 4.9 N 4) 0.49 N
1)2.5 N
contact force, normal force and
22. Let F, F, and f denote the magnitude of the
on the other kept in contact. If none of
the friction exerted by one surface
these is zero

a. F> F, b. F> f C. F, > f d. F,- f <F< F,t f

2) b & c are correct
l) ac are Correct
3) a, b & dare correct 4) only a & bare correct

17
CO -SPARK
23. If l and u, are the coefficients of limiting. kinetic
and
between two given surfaces. Arrange them in descending order rolling
2) H,and u,
8. A
3) u,,andu, 4) P,and ,
Matrix Match Type: 1

Column - I Column - II 29.

be
a) static fiction 1) constant for given pair
of suria t

b) Limiting fiction 2) dimension less quantity

c) Kinetic friction 3) self adjusting
Comp
d) Rolling fiction 4) has the least magnitude
normal reaction

Multi Correct Choice Type:

25. A block is placed on a rough floor and a horizontal force F' is applied ..
The force of fiction f by the floor on the block is measured for different te
of F and a graph plotted between them
a) is a straight ine of slope 45°
b) is a straight line of slope less than 45° 30.
c) is astraight line of slope 45° for small F and a straight line parallel to
axis for large F. 31.
d) there is a small kink on the graph
1) b & d are correct 2) a is correct 32.
3) c & dare correCt 4) 1 8 2are correct

JEE MAIN & ADVANCED LEVELJE

26. A body of mass 10kg lies on a rough horizontal surface. WVhen a horizo. 33.
force of F newtons acts on it, it gets an acceleration of 5m/s² and wher.
horizontal force is doubled, it gets an acceleration of 18 m/s². Then
coefficient of friction between the body and the horizontal surface
íassume g = 1Oms-)
1) 0.2 2) 0.8 3) 0.4 4) 0.6
27. A uniform chain of length L' hangs partly from a table which is kep:
equilibrium by friction. The maximnum length that can stand without slippE
'!'. then the coefficient of friction between the table and
the is chain
2) L-1
L-I L 31 4)
L-I

18
CO -SPARK
 FRICTION PHY8ICs-CLASs VII
28 A weight W rests on a
rough horizontal plane. If the angle of friction is 0, the
least force that can move the body
along the plane will be
1) # cos 2) Wtan
4) W
sin 0
29 A lineman of maSN 60kg is
holding a
between his hands and the pole is 0.5.vertical pole. The coefficient of static friction
If he is able to climb up the pole,
should press the pole with his hands? (g-what
the minimum foree with which he is
1Om/
) 1200 N 2) 600 N 3) 300 N 4) 150 N
Comprehension Type:
Consider the situation shown in figure.
1.0 kg 1.0kg

=0.2 u=0.2

0.5 kg
30. The acceleration of the 1.0kg blocks is
1) 1.6 m/s? 2) 2.8 m/s? 3) 4.5 m/s² 4) 0.4 m/s?
31. The tension in the string connecting the
1.0kg blocks is
1) 2.4 N 2) 4.8 N 3) 1.02N 4) 6.3 N
32. The tension in the string attached to 0.50kg.
1) 1.02N 2) 4.8 N 3) 2.4 N 4) 6.3 N

JEE MAIN & ADVANCED LEVEL4

33. Aforce F is applied on a block of mass m as shown in the figure. What will be the
maximum value of F such that the block will not move. The coefficient of friction
between block and floor is 0 =cons tant|

urmg 2)F = mg mg
+u sin 0 3) cos
4)
Sin 0 cos sind + 4 COs

CO -SPARK 19