HAI-F YEARLY EXAMTNATION : 2014-15

CLASS * Xl

SUBSJECT - PHYSICS

MAX.MARKS - 70

TIME - 3 hrs

General instructions:

'/ There are 26 number of questions in this paper.

mark each, Question nurnber six to ten are short answer type questions containstwo mark each, Question number eleven to twenty two contains three mark each,question number twenty three is value based question contains four marks andQuestion number twenty four to twenty six contains five mark each .

no. (6) of two marks, question no.(12) of ihree marks and questions no.(24 ),(25)and questions no. (26))of five marks .

lf x = a + bt2,where x is in meter and t in seconds ,find the units +f ,a, and ,b,.

What is the angle of friction between two surfaces in contact if the coefficient of1

-,Sli".v3

Q.3 What is the angle between the direction of the,force and displacement for maximum . 1

and minimum work done?

How wilt the kinetic energy change if the momentum of a particle is doubled?

What is the weight of a body at the centre of the Earth?

An experiment measures quantities a ,b and c . X is calculated from the formula X =abl* the percentage errors in a , b ,c are lLo/o ,*zo/o , l3o/o respectively.what is

the percentage error in X?

OR

check whether the following relation is dimensionally correct or not

Fs =1 mv2,)mu,

where F is the force, s is distance, u and v are the initial and final velocities

respectively.'

The displacement of a particle startingfrom rest (att = 0) is given by x = Gt2-t3

L

T

Q.1

Q.2

L

L

2

Q.4

Q.s

Q,6

Q.7

DJ-Phy-xH/2'40 (11

Q.8

Q.e

.calculate the time at which the particle attains zero velocity again'

Prove that it ii easy to pull than to push a lawn roller"

Define torque. write an expression for it and discuss the conditions when the torque

is minimum and maximum..?

Q.1O Assuming the Earth to be a sphere of uniform mass density, how much would a body

weighhalfwaydowntothecentreoftheEarthifitweighed250\onthesurface?

Q.11 Convert 10 Newton into dyne using dimensional analysis.

Q.12 Derive an expression for centripetal acceleration of a particle moving with uniform

speed v along a circular path of radius r'

OR

. Define uniform motion. Draw the velocity -time graph firr an object in uniform

motion. Show that the area u.nder the velocity -time graph gives the dlsplacement of

an object in given time interval' 5 N. rf the angre

Q.13 Two forces whose magnitude are in the ratio of 3 : 5 give a resultant 3

of inclination is 600 ,Find the magnitude of each force.

Q.14 Define the term impulse. prove the impulse momentum theorem'

ion for the work done against theQ.xs-JAlitb-i8i@,f1-4'd a n expressi

friction when a body is made to slide down an inclined plane'

Q.16 State and prove the work energy theorem'

Q.17 What are conservative and non conservative forces? Give one example of each'

f -'il,t,lar rnrlmanl the motion of aQ.18 State the law of conservation of arigular momentum' Hence explain

ballot dancer.

Q.19 Find the scalar and vector product of two vectors a = 3i - 4i + 5k and b = -2i -i -'l:

e.20 Derive a relation for the orbitaf velocity of a satellite orbiting very close to the surface

ofthe Earth.

e.21 Derive a relation which shows that the value of ecceleration due to gravity 'g

decreases with altitude or herght'

Q.22, A 400kg satellite is in a circular orbit of radius 2R5 about the Earth' How much energy 3

is required to transfer it in a circular orbit of radius 4Rr? what are the changes in

kinetic energy and potential energies?

2

2

3

3

3

3

3

3

3

3

3

Dt-Phy-x1412440(2)

e.23 ln a tug of war match between two teams A and B, Team A won the match. During

the event some of the players of team B got injured as the team A dragged them on 4

\ were laughing on the players of team B, Howeverthe ground. PlaYers of team I

Ashok, the captain of team A went to the doctor. He told the doctor that some players

have been injured on the ground. Doctor came to the ground and treated the injured

players It

(i) What type (positivd ,negative ,or zero) of the work is done by team A? \

(ii) What type(positive,negative,or zero) of the

(iii) What values are shown by Ashok?

byteam B? I

e.24 (a) Derive a relation between linear velocity and angular velocity in a uniform circular

motion.

(b) prove that the maximum horizontal range isr.four times the maximum height

attained by a projectile which is fired along the required oblique direction.

OR

State parallelogram law of vector addition. Two vectors A and B are inctined to each

.,, - lhs,tgk?gan!&gg#lrqug[gillg!.gff3n lary-of]e9tot-la{',!p" ,Find analvticallv

the magnitude and direction of their resultant .What is the magnitude of resultant

when (i) 0 = 00 (ii)O = 900 (iii) e = 1800

e.25 (a) What is limiting friction? State three laws of limiting friction also define the

coefficient of limiting friction.

(b) Two masses 8 kg and L2 kg are connected at two ends of a light inextensible string

that goes over a frictionless pulley of negtigible mass .Find the acceleration of the

. masses and tension in the string when masses are released.

OR

What is meant by banking of roads? What is the need of banking of roads? Obtain an

expression for the maximum speed with which a vehicle can safely negotiate a curved

road banked at an angle 0. The coefficient of friction between the wheels and the

road is;,r.

e.26 What is rolling motion? Write an expression for the total kinetic energy of a rolling

work is done{-\L---

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@FrYF

body, Also derive an expression for the total kinetic energy of a rolling (i) solid

sphere (ii) hollow sphere (iii) solid cylinder.

OR

n of paratlel axes. Obtain a relation for the moment of inertia of a

(ii) A rope of negtigible rnass is wound round a hotlow cylinder of mass 3 kg and radius

40 cm.,What is the angular acceleration of the cylinder if the rope is pulled with a

force of 30N? Whatiis the linear: acceleration of the rope? Assume that there is no

slipping

DI-Phy11P472446 (41

MARK!NG SCHEME

CU M U TATIVE EXAMI NATION.2O14.15

crAss-xr(PHYslcs)

s.No. Answer / explanation Weitage

Q.1 a meter, b m/sz LL +22Q.2 Angte of friction 0 = 300 1

Q.3 for maximum 0 = 0' for minimum 0 = 90' 1a !22

Q.4 K.E. become four times of its initial value L

Q.s Zero tQ.6 By accurate calculations find percentage error in X= *13o/o 2

Q.7 'Tofind V= 12t -3t',substituteV=0and Bett =4second L+LQ.8 Accurate explanation 2

Q.9 Definition of torque and formula+ two conditions L+L =2

Q.10 By proper formula and accurate calculations find acceleration due to gravity 96 =g/2 and calculate new weight = 125N

1+1

Q.11 Proper calculations and to find 10 N = 10o dyne 3

Q.12 Correct derivation for the centripetal accelerationOr

Correct definition + accurate graph + displacement

3

L+L+L=3

.-t Si-@:'E.f Fr = 15N Fz = 251{' 5

Q.14 Definition + proof t+2=3Q.1s To find w = tng (p1cos 0 - sin 0)S where symbols have their usual meaning. 3

Q.16 Correct statement + proof L+2=l-

Q.17 Correct definition of conservative and non conseryative forces+one example ofeach

1+1+1

Q.18 Correct statement + correct explanation L+2=3Q.19 To find a.bl-2'5 and aXb = 7i* j - 5 k L 1

Lz+ Lz

Q.20 To find vo = {EE_ 3

Q.21 To find rn = g1rff) 3

Q.22 By correct calcutations to find change in total energy AE = 3.13 x 10'j , AK = -3.13 x

loeJ,AV=-6.25x10ejzl +!22

Q.23 (i)Positive work done (ii) negative work done (iii)Ashok is good sport

man,concerned for bthers,helpful and kindL+ L+2

Q.24 (a) Derivation for v = a)r (b) derivation for R max = 4H

OR

Statement+Derivation for resultant and direction + three cases

-/

t '

2%+2%

L+2Tz + L%

Q.25""" {a} definition + three laws + definition of coefficient of limiting fr:iction'Use

the formula for acceleration and tension from derivation of connected motion

and find (b) acceleration a = 2mls2 , tension T = 95N

'oRCorrect definition+proper explanation for need of banking roads + accurate

derivation for speed

r# xg*1=3''221+1

t+1A+ 3/z

Q.25 Definition + expression for total K.E. in rolling motion+ total K.E. for solid sphere

{ rr'* total K.E.for hollow sphere f { mv2 + totat K.E.for solid cylinder E imv2

OR

(a) correct statement and derivation for the relation+ (b) correct solution for the

linear acceleration ( a =10m/s2)

1+1+1+1+1

L+2+2.

a+jiiiaY;:itsl

' . :..1-1.''. -,:,'ilii9:]1

.',- 1 ir.F.i:itrir-.i1l