40048 + Interview Questions in Physics in Class 11

1.	A bucket filled with water having a mass of 15 kg is raised from a well of depth 12 m with the help of a rope. If the work done to do so is 2160j, the linear density of the rope is
Answer» 0.2 kg/m 0.1 kg/m 1 kg/m 0.5 kg/m Answer :D

Discussion

2.	The temperature inside a refrigerator is t_2^@C and the room temperature is t_1^@C. The amount of heat delivered to the room for each joule of electrical energy consume ideally will be _____
Answer» `(t_2+273)/(t_1-t_2)` `(t_1+t_2)/(t_2+273)` `(t_1)/(t_1-t_2)` `(t_1+273)/(t_1-t_2)` Solution :COEFFICIENT of PERFORMANCE of a refrigerator , `ALPHA =Q^2/W` Heat RELEASED in reservoir`Q_1=W+Q_2` `therefore Q_2=Q_1-W` `therefore alpha=(Q_1-W)/W=Q_1/W-1` `therefore Q_1/W=alpha+1` but `alpha=(t_2+273)/(t_1-t_2)` `therefore Q_1/W=(t_2+273)/(t_1-t_2)+1` `=(t_2+273+t_1-t_2)/(t_1-t_2)` `therefore Q_1/W=(t_1+273)/(t_1-t_2)`

Discussion

3.	A solid material is supplied heat at a constant rate. The temperature of the material is changing with the heat input as shown in figure. Study the graph carefully and answer the following questions: (i) What do the horizontal regions AB and CD represent? (ii) If CD = 2AB, what do you infer? (iii) The slope of OA gt the slope of BC. What does this indicate? (iv) What does the slope DE represent ?
Answer» Solution :(i) In the regions AB and CD the temperature of the material REMAIN constant. So AB represents fusion and CD represents vaporisation. (ii) `CD = 2AB or Q_(4) = 2Q_(2)`, it shows that latent heat of vaporisation is twice than that of latent of fusion. (iii) Let `C_(1)` and `C_(2)` are the specific heats of SOLID and liquid states respectively, then `Q_(1) = mC_(1) Delta T_(1) (or) C_(1) = 1/(m((DeltaT_(1))/Q_(1)))=1/(mxx "slope of" OA)` Similarly `C_(2) = 1/(m XX "slope of" BC)` , Since slope of `OA gt` slope of BC, `therefore C_(1) gt C_(2)`. (iv) If `C_(3)` is the specific heat of vapour state (region DE), then `C_(3) = 1/ (m xx "slope of" DE)` (or) Slope of `DE = 1/(mC_(3))=1/("heat capacity"). `

Discussion

4.	Choose INCORRECTstatement
Answer» Particles in the MEDIUM vibrate about their mean POSITIONS with the same amplitude No particles remains at rest PERMANENTLY during wave propagation The different particle pass through the mean position move with differentmaximum VELOCITY The phase at EVERY particle ranges from a 0 to `2pi`. Answer :C

Discussion

5.	Consider a simulation with a car of mass 1000 kg moving with a speed 18.0 km/h on a road and colliding with a horizontally mounted spring of spring constant 6.25xx10^(3)Nm^(-1). Taking the coefficient of friction, mu to be 0.5 What is the maximum compression of the spring ?
Answer» Solution :In presence of friction, both the spring force and the frictional force act so as to oppose the compression of the spring. We invoke the WORK - energy theorem, rather than the conservation of mechanical energy. The chenge in kinetic energy is `Delta K = K_(f)-K_(i)=0-(1)/(2) m u^(2)` The work done by the net force is `W=-(1)/(2)kx_(m)^(2)-mu mg x_(m)` Equating we having `(1)/(2)m u^(2)=(1)/(2)kx_(m)^(2)+mu mg x_(m)` Now `mu mg = 0.5xx10^(3)xx10=5xx0^(3)N` (taking `G = 10.0 ms^(-2)`). After rearranging the above EQUATION we obtain the following quadratic equation in the unknown `x_(m)`. `kx_(m)^(2)+2mu m g x_(m)-m u^(2)=0` `x_(m)=(-mu mg +[mu^(2)m^(2)g^(2)+mku^(2)]^(1/2))/(k)` where we take the positive square root since `x_(m)` is positive. Putting in numerical VALUES we obtainthe following quadratic equation in the unknown `x_(m)=1.35m`.

Discussion

6.	An object is projected with a velocity sqrt((8gR)/(3)) from earth. The velocity of the object, at the maximum height reached by it will be
Answer» `SQRT((2gR)/(3))` `sqrt((8R)/(3))` `sqrt(2gR)` zero Answer :A

Discussion

7.	Ice starts forming on a lake with water at0^(@)C, when the atmospheric temperature is -6^(@)C. If the time taken for 1 cm of Ice to be formed is 5 hours, then time taken for thickness of ice to change from 1 cm to 2 cm is
Answer» 20 Hr. 10 Hr. 15 Hr. 25 Hr. Answer :C

Discussion

8.	Give the uses of polar satellites.
Answer» SOLUTION :POLAR satellites are uses in weather and environment monitoring. They are USED in spying work for military purposes. They are used to study topography of Moon, VENUS and MARS.

Discussion

9.	What is the dimensional formula for impluse
Answer» `ML^(2)T^(-1)` `MLT^(-2)` `MLT^(-1)` `M^(0)L^(-1)T^(-1)` SOLUTION :Dimensionof impulse`=F XX Delta t` Impulse `=[MLT^(-2) ] [T]` `=[MLT^(-1)]`

Discussion

10.	(A) The illuminance of an image produced by a convex lens is greater in the middle and less towards the edges. , ( R) the middle part of image is formed by undeflected rays while outer part by inclined rays.
Answer» Both A and R are true and R is the correct explanation of A Both A and R are true and R is not the correct explanation of A A is true and R is false Both A and R is false Answer :A

Discussion

11.	Two metal rods 1 and 2 of the same length have same temperature difference between their ends. Their thermal conductivities are K_1 and K_2 and cross-section areas A_1 and A_2 respectively. What is therequired condition for the same rate of heat conduction in them?
Answer» SOLUTION :`(Q)/( t) = KA ( ( theta_1 - theta_2 ) )/( x )`, but `(theta_1 - theta_2)/( x )` is the same for both. For the same rate of heat conduction `KA= a` CONSTANT if `K_1 A_1 = K_2 A_2`.

Discussion

12.	A particle executes shm with a period 8 s. Find the time in which half the total energy is potential.
Answer» Solution :T = 8s Total energy `= 1/2 momega^2a^2` POTENTIAL energy`=1/2 m OMEGA^2y^2` where y is the DISPLACEMENT of the PARTICLE from the equilibrium position Given that `1/2 XX`Total energy = Potential energy `1/2[1/2momega^2a^2]=1/2momega^2y^2` `1/2a^2=y^2` `y=a/sqrt2` `omega=(2pi)/T=(2pi)/8=pi/4` `y= a sin omegat= a sin""(pi)/4t` `a/sqrt2 = a sin""pi/4t` `sin""pi/4 = sin""pi/4t` `pi/4 = pi/4t` t = 1 s

Discussion

13.	An engine is attached to a wagon through a shock absorber of length 1.5 m. The system with a total mass of 50,000 kg is moving with a speed of 36 ^kmh(-1) when the brakes are applied to bring it to rest, the spring of the shock absorber gets compressed by 1.0 m. If 90 %of energy of the wagon is lost due to friction, calculate the spring constant.
Answer» Solution :m = 50,00 kg v = 36 km/h ` = (36xx1000)/(60xx60)` = 10 m/s X = 1.0 m ` K = 1/2 mv^(2)` ` = 1/2 xx 50000 xx(10)^(2)` ` = 25000 xx100 J ` `= 2.5 xx10^(6)` J Since , 90 % of KE of the system is lost due to friction , therefore 10 % energy transferred to SHOCK ,absorber , is given by `Delta E = 1/2 kx^(2)` `DeltaE = 10 % of K ` ` :. 1/2 kx^(2) = 10/10 xx2.5 xx10^(6) J ` ` :. k = 5.0 xx10^(5) ` N/m

Discussion

14.	Why are telephone wires often given snag?
Answer» SOLUTION :This is ALLOWED for CONTRACTION in WINTER.

Discussion

15.	A particle is in linear simple harmonic motion between two points. A and B, 10 cm apart (figure) take the direction from A to B as the positive direction and choose the correct statements.
Answer» The sign of velocity, acceleration and FORCE on the particle when it is 3cm AWAY from a going towards B are positive. The sign of velocity of the particle at C going towards B is negative. The sign of velocity, acceleration and force on the particle when it is 4cm away from B going towards A are negative. The sign of acceleration and force on the particle when it is at points B is negative. Solution :When the particle is 3 CM away from A going towards B. So velocity is positive because direction from A to B is positive and acceleration is always towards mean position and so acceleration is positive and HENCE force is also positive. So statement A is correct. When particle is at C, velocity is towards B hence positive. Hence, Statement B is incorrect. When the particle is 4 cm away from B going towards a velocity is negative and acceleration is towards mean position hence negative so statement C is correct. Acceleration is always towards mean position in SHM. When the particle is atB, acceleration and force are towards B to A that is negative. Hence, statement D is correct.

Discussion

16.	Which of the following is a dimensional constant?
Answer» REFRACTIVE index Poisson.s ratio Relative density Gravitational constant Answer :A

Discussion

17.	A person is walking in rain feels the velocityof rain as twice to his velocity. At which angle he should hold the umbrella with vertical if he moves forward, if it is raining vertically downwards
Answer» `30^(@)` `45^(@)` `60^(@)` `90^(@)` ANSWER :A

Discussion

18.	A ring is allowed to roll down on an incline of 1 in 10 without slipping. The acceleration of its centre of mass is
Answer» `9.8ms^(-1)` `4.9ms^(-2)` `0.98ms^(-2)` `0.49ms^(-2)` ANSWER :D

Discussion

19.	In the question number 25, if the mass placed at vertex A is doubled, then the force acting on the mass 2m placed at the centroid O is
Answer» ZERO `(2Gm^(2))/(l^(2))` `(5Gm^(2))/(l^(2))` `(6Gm^(2))/(l^(2))` Solution :(d) Force on MASS 2m at O due to mass 2m at A is `F'_(OA)=(G(2m)(2m))/((1//sqrt(3))^(2))=(12Gm^(2))/(l^(2))` along OA `:.` The resultant forece on the mass 2m at O due to masses at A,B and C is `F'_(R)=F'_(OA)-(F_(OB) sin30^(@)+F_(OC) sin30^(@))` `(12Gm^(2))/(l^(2))-((6Gm^(2))/(l^(2))xx(1)/(2)+(6Gm^(2))/(l^(2))xx(1)/(2))=0` `= (12Gm^(2))/(l^(2))-(6Gm^(2))/(l^(2))=(6Gm^(2))/(l^(2))` along OA

Discussion

20.	What is the escape velocity from a black hole ?
Answer» SOLUTION :`implies (v_e) GT c` (VELOCITY of LIGHT)

Discussion

21.	Does friction occurin liquid and gases.
Answer» SOLUTION :Frictionalsooccursin LIQUIDAND gasescollectivelycalledfluids .Butunlikethefrictionbetweensolidssurfacesfluidfrictiondoesdependsuponspeedand AREAOF CONTACT.

Discussion

22.	The surface tension of water at critical temperature is …….
Answer» ANSWER :ZERO.

Discussion

23.	A sphere is perfroming pure rolling a shown in the figure. The radius of curvature of trajectory of point A in the shown position is XR. Find 2x.
Answer» 3 4 1 0 Answer :A

Discussion

24.	Two skaters A and B weighing 40 kg and 60 kg respectively stand facing each other 5 m apart. If they pull a light rope stretched between them, then they meet
Answer» `1.5m` from A `2M` from A `2.5m` from A `3.0m` from A Answer :D

Discussion

25.	How many joules make up one erg?
Answer» SOLUTION :`10^(7)` ERG = 1 JOULE 1 erg = `10^(-7)` Joule

Discussion

26.	A drill machine made of steel is rotating at the rate of 180 rpm to make a hole on a steel plate. Total mass of the drill and the plate is 180 g. If the whole part of the mechanical energy is converted into heat and if the temperature of the plate rises by 0.5^(@) C, then determine the power of the drill machine and the magnitude of the torque acting. [ Specific heat capacity of steel = 0.10 cal. g^(-1).""^(@)C^(-1)]
Answer» ANSWER :37.8 W, 2.045 N.m

Discussion

27.	For pure water and clean glass, the angle of contact is
Answer» `0^@` `8^@` `138^@` `90^@` ANSWER :A

Discussion

28.	If force acts on a body, whose line of action does not pass through its CG, then the body will experience
Answer» ANGULAR ACCELERATION lineal acceleration both (a) and (b) NON Answer :C

Discussion

29.	Eleven forces each equal to 5N act on a particle simultaneously. If each force makes and angle 30^(@) with the next one, the resultant of all forces is
Answer» 15N 55 N 5 N zero Answer :C

Discussion

30.	(A): The strain produced in a stretched spring is shearing(R) : When spring is stretched shape of the spring changes but not its linear dimension
Answer» Both (A) and (R) are TRUE and (R) is the CORRECT explanation of (A) Both (A) and (R) are true and (R) is not the correct explanation of (A) (A) is true but (R) is false Both (A) and (R) are false Answer :A

Discussion

31.	A certain force increases the length of a wire by 1 mm. The force required to increases its length by 2 mm is …………… .
Answer» 2F 4 F 8 F 16 F SOLUTION :`Delta l PROP F`

Discussion

32.	Angular position theta is scalar where angular displacement Deltatheta is vector.
Answer» ANSWER :TRUE.

Discussion

33.	Three bodies each of mass 'm' are placed at the three corners of a square of side 'a'. The gravitational force on unit mass kept at the fourth corner is
Answer» `(GM)/(3a^2)` `(Gm)/(SQRT(3)a^2)` `(3Gm)/(a^2)` `(Gm)/(a^2) (sqrt(2)+(1)/(2))` ANSWER :D

Discussion

34.	What are the factors on which escape velocity depends on ?
Answer» Solution :`implies`Mass of earth (planet), RADIUS of earth and VALUE of acceleration DUE to gravity.

Discussion

35.	A car and truck have same momentum. Which will have more kinetic energy ?
Answer» Solution :From the expression `K=(p^(2))/(2m)` If .p. is constant, .K. is INVERSELY proportional to the mass of the body. Hence, the KINETIC ENERGY of the CAR is more than that of the truck.

Discussion

36.	Two bodies with moment of inertia I_(1) and I_(2) (I_(1) gt I_(2)) are rotating with same angular momentum. If K_(1) and K_(2) are their kinetic energies, then
Answer» `K_(2) gt K_(1)` `K_(2) lt K_(1)` `K_(1)=K` `K_(2) GE K_(1)` Answer :B

Discussion

37.	Which of the following quantities remain constant in a planetory motion (consider elliptical orbits) as seen from the sun?
Answer» speed angular speedd kinetic energy angular momentum Answer :D

Discussion

38.	Give an example to show that the following statement is false. Any two forces acting on a body can be combined into single force that would have same effect.
Answer» SOLUTION :(i) Consider two equal and opposite forces ACTING on a wheel. (II) If two forces combined and acting on SINGLE point on the wheel, there will be no EFFECT. However, if they act separately on the edges of the whell, there will be a rotating effect. (iii) This example falsifies the given statement.

Discussion

39.	A discrevolves with a speed of 33/3rev/min, and has a radius of 15 cm. Two coins are placed at 4 cm and 14 cm away from the centre of the record. If the co-efficient of friction between the coins and the record is 0.15, which of the coins will revolve with the record ?
Answer» Solution :For the coin to revolve with the DISC, the force of friction should be enough to PROVIDE thenecessary centripital force `i.e (mv^2)/( r) lt= MU MG ` . Now `v = r omega` , where ` omega = (2pi)/( T)` is the angular frequency of the disc.For a given `mu` and `omega` , the condition is `r lt= mu G// omega^2 ` .The condition is satisfied by the nearer coin ( 4 cm from the centre).

Discussion

40.	In a double star system, two stars of masses m_(1)" and "m_(2) seperated by a distance d rotate about their centre of mass. Then their common angualr velocity would be
Answer» `sqrt((Gm_(1))/(d^3))` `sqrt((Gm_(2))/(d^3))` `sqrt((G(m_(1)+m_(2)))/(d^3))` `sqrt((d^3))/(G(m_(1)+m_(2)))` ANSWER :C

Discussion

41.	A solid cylinder of mass 20 kg rotates about its axis with angular speed 100 rad/s. The radius of the cylinder is 0.25 m. What is the kinetic energy associated with the rotation of the cylinder ? What is the magnitude of angular momentum of the cylinder about its axis ?
Answer» Solution :Given: M=20kg, `omega=100"rad"s^(-1), R=0.25m` M.I of the CYLINDER about its own AXIS, `I=1/2MR^(2)=1/2xx20xx(.25)^(2)` `=10xx0.0625=.625kgm^(2)` ROTATIONAL K.E. `I=1/2 I omega^(2)` `=1/2 xx0.625xx(100)^(2)` `=0.3125xx10^(4)=3125J` Angular momentum, `L=I omega=0.625xx100` `=62.5 kg m^(2)s^(-1)`

Discussion

42.	The following equations represent transvers waves : z_(1)=A cos (ky-omega t). Identify the combination (s) of the waves which will produce (i) standing waves (s), (ii) a wave travelling in the direction making an angle of 45^(@) with the positive x and positive y-axes. In each case find the positions at which the resultant intensity is always zero.
Answer» Answer :1 and 2 combine to form stationary waves; `x=(2s+1) pi//2k`. 1 and 3 combine to form progressive WAVE MAKING an angle of `45^(@)` with x and y-axis; `x=y pm (2s+1)pi//k`

Discussion

43.	A force of 150N produces an acceleration of 2ms^(-2) in a body and a force of 200N produces an acceleration of 3ms^(-2). The mass of the body and the coefficient of kinetic friction are
Answer» 50KG, 0.1 25kg , 0.1 50kg , 0.5 50kg , 0.2 Solution :`F-f=ma, f=mu_(K)MG`

Discussion

44.	The equation for the displacement of a particle executing SHM is y = {5 sin pit} cm. Find (1) the velocity at 3cm from the mean position, (ii) acceleration after 0.5s after leaving the mean position.
Answer» `3picms^(-1), "zero"` `5picms^(-1), "zero"` `4picms^(-1), 5PI^(2)cms^(-2)` `2picms^(-1), "zero"` Answer :C

Discussion

45.	Can a system be heated and its temperature remains constant ?
Answer» Solution :Yes, this is possible when the ENTIRE HEAT SUPPLIED to the system is utilized in EXPANSION. This implies that heat supplied should perform WORK against the surroundings.

Discussion

46.	(A) we can produce a real image by plane or convex mirrors under certaincircumstances. (R ): The focal power of a convex mirror is always taken as positive.
Answer» Both A and R are TRUE and R is the correct EXPLANATION of A Both A and R are true and R is not the correct explanation of A A is true and R is false Both A and R is false Answer :C

Discussion

47.	Infinitesimal quantity means
Answer» COLLECTIVE particles extremely small nothing Extremely LARGER ANSWER :B

Discussion

48.	No work is done by a force on an object if(a) the force is always perpendicular to its velocity.(b) the force is always perpendicular to its acceleration(c ) the object is stationary but the point of application of the force moves on the object (d) the object moves in such a way that the point of application of the force remains fixed.
Answer» B, C & d are CORRECT a, b & d are correct a, c & d are correct all are correct ANSWER :C

Discussion

49.	One way of measuring a person's body fat content is by "weighing" them under water. This works because fat tends to floats on water as it is less dense than water. On the other hand muscle and bone tend to sink as they are more dense. Knowing your 'weight' under water as well as your real weight out of water, the percentage of your body's volume that is made up of fat cab easily be estimated, fat (low density) and everything else (high density). The "weight" measured by spring balance both inside and outside the water. Quotes are placed around weight to indicate that the measurement read on the scales is not your true weight, i.e. the force applied to your body by gravity, but a mersurement of the net downward force on the scale. A person of mass 165 Kg having one fourth of his volume consisting of fat (relative density 0.4) and rest of the volume consisting of everything elese (average relative density (4)/(3)) is weighed under water by the spring balance. The readibng shown by the spring balance is -
Answer» `15 N` `65 N` `150 N` `165 N` Solution :Let `'V'` be the total volume of the person Then , `((V)/(4)) (0.4 xx 10^(3)) + ((3)/(4)V)((4)/(3) xx 10^(3)) = 165 rArr V = (165)/(1100) = 0.15 m^(3)` Reading on spring BALANCE under water is : `W_(app) = [165 xx 10] - 0.15 [10^(3)][10] = 150 N`

Discussion

50.	One way of measuring a person's body fat content is by "weighing" them under water. This works because fat tends to floats on water as it is less dense than water. On the other hand muscle and bone tend to sink as they are more dense. Knowing your 'weight' under water as well as your real weight out of water, the percentage of your body's volume that is made up of fat cab easily be estimated, fat (low density) and everything else (high density). The "weight" measured by spring balance both inside and outside the water. Quotes are placed around weight to indicate that the measurement read on the scales is not your true weight, i.e. the force applied to your body by gravity, but a mersurement of the net downward force on the scale. In the above question if the spring is cut, the accleration of the person just after cutting the spring is
Answer» ZERO `1 m//s^(2)` `9.8 m//s^(2)` `0.91 m//s^(2)` SOLUTION :N//A

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

A bucket filled with water having a mass of 15 kg is raised from a well of depth 12 m with the help of a rope. If the work done to do so is 2160j, the linear density of the rope is

The temperature inside a refrigerator is t_2^@C and the room temperature is t_1^@C. The amount of heat delivered to the room for each joule of electrical energy consume ideally will be _____

Choose INCORRECTstatement

Consider a simulation with a car of mass 1000 kg moving with a speed 18.0 km/h on a road and colliding with a horizontally mounted spring of spring constant 6.25xx10^(3)Nm^(-1). Taking the coefficient of friction, mu to be 0.5 What is the maximum compression of the spring ?

An object is projected with a velocity sqrt((8gR)/(3)) from earth. The velocity of the object, at the maximum height reached by it will be

Ice starts forming on a lake with water at0^(@)C, when the atmospheric temperature is -6^(@)C. If the time taken for 1 cm of Ice to be formed is 5 hours, then time taken for thickness of ice to change from 1 cm to 2 cm is

Give the uses of polar satellites.

What is the dimensional formula for impluse

(A) The illuminance of an image produced by a convex lens is greater in the middle and less towards the edges. , ( R) the middle part of image is formed by undeflected rays while outer part by inclined rays.

Two metal rods 1 and 2 of the same length have same temperature difference between their ends. Their thermal conductivities are K_1 and K_2 and cross-section areas A_1 and A_2 respectively. What is therequired condition for the same rate of heat conduction in them?

A particle executes shm with a period 8 s. Find the time in which half the total energy is potential.

Why are telephone wires often given snag?

A particle is in linear simple harmonic motion between two points. A and B, 10 cm apart (figure) take the direction from A to B as the positive direction and choose the correct statements.

Which of the following is a dimensional constant?

A person is walking in rain feels the velocityof rain as twice to his velocity. At which angle he should hold the umbrella with vertical if he moves forward, if it is raining vertically downwards

A ring is allowed to roll down on an incline of 1 in 10 without slipping. The acceleration of its centre of mass is

In the question number 25, if the mass placed at vertex A is doubled, then the force acting on the mass 2m placed at the centroid O is

What is the escape velocity from a black hole ?

Does friction occurin liquid and gases.

The surface tension of water at critical temperature is …….

A sphere is perfroming pure rolling a shown in the figure. The radius of curvature of trajectory of point A in the shown position is XR. Find 2x.

Two skaters A and B weighing 40 kg and 60 kg respectively stand facing each other 5 m apart. If they pull a light rope stretched between them, then they meet

How many joules make up one erg?

For pure water and clean glass, the angle of contact is

If force acts on a body, whose line of action does not pass through its CG, then the body will experience

Eleven forces each equal to 5N act on a particle simultaneously. If each force makes and angle 30^(@) with the next one, the resultant of all forces is

(A): The strain produced in a stretched spring is shearing(R) : When spring is stretched shape of the spring changes but not its linear dimension

A certain force increases the length of a wire by 1 mm. The force required to increases its length by 2 mm is …………… .

Angular position theta is scalar where angular displacement Deltatheta is vector.

Three bodies each of mass 'm' are placed at the three corners of a square of side 'a'. The gravitational force on unit mass kept at the fourth corner is

What are the factors on which escape velocity depends on ?

A car and truck have same momentum. Which will have more kinetic energy ?

Two bodies with moment of inertia I_(1) and I_(2) (I_(1) gt I_(2)) are rotating with same angular momentum. If K_(1) and K_(2) are their kinetic energies, then

Which of the following quantities remain constant in a planetory motion (consider elliptical orbits) as seen from the sun?

Give an example to show that the following statement is false. Any two forces acting on a body can be combined into single force that would have same effect.

A discrevolves with a speed of 33/3rev/min, and has a radius of 15 cm. Two coins are placed at 4 cm and 14 cm away from the centre of the record. If the co-efficient of friction between the coins and the record is 0.15, which of the coins will revolve with the record ?

In a double star system, two stars of masses m_(1)" and "m_(2) seperated by a distance d rotate about their centre of mass. Then their common angualr velocity would be

A solid cylinder of mass 20 kg rotates about its axis with angular speed 100 rad/s. The radius of the cylinder is 0.25 m. What is the kinetic energy associated with the rotation of the cylinder ? What is the magnitude of angular momentum of the cylinder about its axis ?

A force of 150N produces an acceleration of 2ms^(-2) in a body and a force of 200N produces an acceleration of 3ms^(-2). The mass of the body and the coefficient of kinetic friction are

The equation for the displacement of a particle executing SHM is y = {5 sin pit} cm. Find (1) the velocity at 3cm from the mean position, (ii) acceleration after 0.5s after leaving the mean position.

Can a system be heated and its temperature remains constant ?

(A) we can produce a real image by plane or convex mirrors under certaincircumstances. (R ): The focal power of a convex mirror is always taken as positive.

Infinitesimal quantity means