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12551.

25. A light and a heavy body have equal momentum.Which one has greater kinetic energy?(1). Light body(2) Heavy body(3) Both have equal kinetic energy(4) Data is insufficient

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The light body.

Kinetic energy equation:Ek=1/2mv2Ek=1/2mv2Momentum equation:p=mvp=mvKinetic energy equation in terms of momentum:Ek=p^2/2mEk=p^2/2m

If two objects have the same mass and the same momentum, they have the same kinetic energy.Of a light and a heavy body having equal kinetic energy, the heavy body has more momentum.At equal momentum, the light body has more kinetic energy.

12552.

16. Show that there is a loss of kinetic energy during one dimensional inelastic collision. How will youaccount for this loss of energy?or

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12553.

A uniform circular wire hasresistance 15 ohm. If the length ofwire is doubled by stretching it. Whatis its resistance as the volume of wireis same.

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R=pl/aLet, L=2l A=a/2 (for keeping same volume), R=pL/A 15=pL/AWe have to find, r=pl/aSo, 15=pL/A 15=p2l/(a/2)

15=p 2l2/a15=p 4l/a15/4 = pl/aSo, r=15/4

12554.

i) Write one point of distinction between kinetic energy andpotential energy. What is the role of latent heat in thechange of state of a substance?

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Whilekinetic energyis theenergywhich an object contains because of a particular motion. On the other hand,potential energyis the storedenergy, because of its state of rest.Role of latent heat in state of change of substance :Latent heatdoes not raise the temperature.But thelatent heat has always to be supplied to changethestate of a substance.It is calledlatent heat because it becomes hidden in the substanceundergoing thechange of state,and does not show its presence by raising the temperature.

12555.

16) What is the structure of functional group infollowing classes of organic compounds?i) Estersii) Carboxylic acidsii) Ethersiv) Ketones.

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i) ester. -COO- ii) ether -O-iii) C.A -COOHiv). ketonee. -CO-

12556.

A man is running up hill with a velocity (21+3) m/s w.r.t. ground. He feels that the rain drops are falling verticallywith velocity 4 m/s. If he runs down hill with same speed, find vm

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12557.

3,28 Conssider the D-T reaction (deuterlum-tritium fuslon)(a) Calculate the energy released in MeV in thls reaction from thedata:m(jH )-2.014102 um(H) 3.016049 u(b) Consider the radius of both deuterium and tritium to beapproximately 2.0 fm. What is the kinetic energy nccded toovercome the coulomb repulsion between the two nuclei? To whattemperature must the gas be heated to inttiate the reaction?(Hint: Kinetic energy required for one fusion event saveragethermal kinetic energy available with the interacting particles2(8KT/2); k Boltzman's constant, T absolute temperature.)f atcles, and the radiation

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12558.

A wire elongates by 8 mm when a load of 9 kgis suspended from it. What is the elongationwhen its radius is doubled, if all other quantitiesare the same as before?Ans. 2 mm]

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Young’s modulus Y = Force x L / A x l

Or rewriting we have Y = WL/Al

\l= WL/ AY

Since the length of the wire is on both sides of the pulley length L/2 will be on both sides.

Thus the elongation of the wire in mm is l mm.

hence answer is 2mm

12559.

(d)Both A and R are falseThe area of cross-section of a steel wire (Y 2.0x10"NIm2) is 0.1 cm2. The force required to double its length wil(a) 2x 1012N(b) 2x10"N(c) 2x10°N(d) 2x 10°N

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12560.

Give reason, why does water level rises when a solid object is immersin water.

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an object that sinks displaces an amount of fluid equal to the object's volume. Thus buoyancy is expressed through Archimedes' principle, which states that the weight of the object is reduced by its volume multiplied by the density of the fluid.

12561.

A glass prism deviates the red and the blue rays through 10°and 12°, respectively. A second prism of equal angle deviatesthem through 8° and 10° respectively. Find the ratio of theirdispersive powers.

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12562.

Show how would you on three resistors, each ofresistance 9 Ω so that the equivalent resistance of the combination is(i) 13.5Ω, (ii) 6Ω ?

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1. equivalent resistance = 13.5 ΩJoin two resistors in parallel and one in series as shown in 1st figure We know, in parallel , 1/R' = 1/R₁ + 1/R₂ Here , R₁ = R₂ = R₃ = 9Ω Now, 1/R' = 1/9Ω + 1/9Ω ⇒ R' = 9/2Ω = 4.5 Ω So, equivalent resistance , Req = R' + R₃ [ ∵ R' and R₃ in series ] ∴ Req = 4.5Ω + 9Ω = 13.5Ω

2. Equivalent resistance = 6Ω two resistors are in series which is parallel with 3rd resistor as shown in 2nd figure .now, R' = R₁ + R₂ = 9Ω + 9Ω = 18Ω [ R₁ and R₂ are in series ] now, equivalent resistance, Req = R'R₃/(R' + R₃) [ R' and R₃ are in parallel ] ∴ Req = 18 × 9/(18 + 9) = 18 × 9/27 = 6Ω

12563.

11. Show how you would connect three resistors, each of resistance 612. so thatcombination has a resistance of (1) 9 2. (11) 4 .

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two resistor in parallel and third resistor in series

12564.

2S A unitorm wire of resistance 1000 is melted and recast in a wire of length double that of theoriginal. What would be the resistance of the wire?1)2008]2) 400Ω3) 600Ω4) 100Ω

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12565.

thenthe load is"HA) through 1ΜΩΣ2016 /SET-21.7 Assume that the dioEach Question Carries Ort the diode in the figure has on=0.7 V, but is otherwise ideal.R2k12(+)2V6k1ERThe magnitude of the current i,in mA) is equal toR$Resistor R in the circuit below has been adjusted so that I = 1 mA.The bipolar transistors Q1 and Q2 are perfectly matched and have11a nta are nemligible

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12566.

What are dia, para and Ferromagnetic materials ? Discuss their importantproperties.

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Diamagneticmaterials have a weak, negative susceptibility to magnetic fields. Diamagnetic materials are slightly repelled by a magnetic field and the material does not retain the magnetic properties when the external field is removed. In diamagnetic materials all the electron are paired so there is no permanent net magnetic moment per atom. Diamagnetic properties arise from the realignment of the electron paths under the influence of an external magnetic field. Most elements in the periodic table, including copper, silver, and gold, are diamagnetic.

Paramagneticmaterials have a small, positive susceptibility to magnetic fields. These materials are slightly attracted by a magnetic field and the material does not retain the magnetic properties when the external field is removed. Paramagnetic properties are due to the presence of some unpaired electrons, and from the realignment of the electron paths caused by the external magnetic field. Paramagnetic materials include magnesium, molybdenum, lithium, and tantalum.

Ferromagneticmaterials have a large, positive susceptibility to an external magnetic field. They exhibit a strong attraction to magnetic fields and are able to retain their magnetic properties after the external field has been removed. Ferromagnetic materials have some unpaired electrons so their atoms have a net magnetic moment. They get their strong magnetic properties due to the presence of magnetic domains. In these domains, large numbers of atom's moments (1012to 1015) are aligned parallel so that the magnetic force within the domain is strong. When a ferromagnetic material is in the unmagnitized state, the domains are nearly randomly organized and the net magnetic field for the part as a whole is zero. When a magnetizing force is applied, the domains become aligned to produce a strong magnetic field within the part. Iron, nickel, and cobalt are examples of ferromagnetic materials. Components with these materials are commonly inspected using the magnetic particle method.

12567.

fferentiate amongst dia, para and ferro magnetism. Descingevin'stheory of Paramagnetism.

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Diamagnetic Material

A material that turns at a right angle to the field by producing a magnetic response opposite to the applied field is called diamagnetic material such as silver, copper, and carbon have permeability’s slightly less than free space (for copper, μr= 0.9999980).

Paramagnetic Material

A material aligning itself with the applied field is called paramagnetic material. Paramagnetic materials such as aluminum and air have permeability’s slightly greater than that of free space (for air μr=1.0000004). The effects of diamagnetic and paramagnetic are negligibly small so that materials possessing these weak phenomena are said to b non-magnetic.

Ferromagnetic Material

Within the paramagnetic class of materials, is a special classification of materials called ferromagnetic material. These materials are strongly attracted to magnets and exhibit Paramagnetism to a phenomenal degree. Ferromagnetic materials such as iron, steel, cobalt and their alloys have relative permeability’s extending into the hundreds and thousands, are said to be magnetic.

The magnetic properties of matter are associated with the spinning motion of electrons in the third shell of the atomic structure.

Paramagnetismis a form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. ... Due to their spin, unpaired electrons have a magnetic dipole moment and act like tiny magnets.

12568.

01. A parallel plate capacitor of plate area A and plateseparation d is charged to potential difference V andthen the battery is disconnected A slab of dielectricconstant K is then inserted between the plates of thecapacitor so as to fill the space between the plates. If Q,|E and W denote respectively, the magnitude of chargeon each plate, the electric field between the plates (afterthe slab is inserted), and work done on the system, inquestion, in the process of inserting the slab, then2d k(3) E KdAll of these

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12569.

The engine of a motorcycle can produce a mai mdacceleration 5 m/s. Its brakes can produce a manretardation 10 m/s. What is the minimum time in wcan cover a distance of 1.5 km[Pb. PM la(a) 30 sec(b) 15 sec(c) 10 sec(d) 5 sec

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Let’s say that the bike starts from zero and accelerates at 5m/s^2 for t secs until it reaches v m/s

Then (v-0)/t = 5 or v=5t , and -v = -5t

If T is the total time then there is T-t secs left to stop using a deceleration of

-10 m/s^2 ,so

(0-v)/(T-t) =-10

-v = -10T +10t but -v = -5t , so

-5t = -10T + 10t

10T = 15t

T = 3t/2

Now use the piece of information given the distance 1500m

[1/2] v T = 1500

v T =3000 . Note we have v and T in term of one [1] unknown t

[5t][3t/2]=3000

15t^2 = 6000

t^2 = 400

t=20

So T = 3t/2= 3[20]/2 = 30 secs is the shortest time to complete the journey given the conditions.

therefore answer is 30secs

12570.

9. The equivalent resistance between points X and Y in thefigure is 1ohm. The value of the middle resistance would be(b) 12(a) 3(d) 99(c) 622

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2+1 ll 2+13*3/3+3=1.51.5 ll?1.5*3/1.5+3=1

3 ohm is correctStups are given👆👆

12571.

2016 / SELLAssume that the diodethe diode in the figure has Von=0.7 V, but is otherwise ideal.Each Question2k1252v622 ZRe magnitude of the currenti, in mA) is equal to

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12572.

/As shown in Fig.7.40, the two sides of a step ladder BA and CA are 1.6 m long andhinged at A. A rope DE, 0.5 m is tied half way up. A weight 40 kg is suspended froma point F, 1.2 m from B along the ladder BA. Assuming the floor to be frictionlessand neglecting the weight of the ladder, find the tension in the rope and forcesexerted by the floor on the ladder. (Take g 9.8 m/s?)(Hint: Consider the equilibrium of each side of the ladder separately.)

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12573.

tress versus strain graphs for wires of two materials A and B are as shown in the figure. If Ya and Ye are the Youngsmodulii of the materials, then(a) Ya = 2Y4600 441300Strain →

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12574.

A particle starts from rest. Its acceleration(D)450 m/s(a) versus time (t) is as shown in the figure.The maximum speed of the particle will be:(A) 110 m/s(C) 550 m/s10ms(B) 55 m/s(D) 660 m/st(s)

Answer»

The maximum speed of the particle corresponds to the area of the a→t graph.

Maximum speed = Area of the graph

= 1/2 ×10 × 11

= 55 m/s

12575.

Example 18. A 3 m long ladderweighing 20 kg leans on a friction-twall. Its feet rest on the floor 1 mfrom the wall as shown in Fig. 7.33Find the reaction forces of the wall3 mD242mand the floor. [NCERT; Delhi 171 WSolution. The ladder AB ism long, its foot Ais at distance Ac

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12576.

5. A driver of a car travelling at 52 km h applies the brakes andaccelerates uniformly in the opposite direction. The car stopsin 5 s. Another driver going at 3 km h' in another car applieshis brakes slowly and stops in 10 s. On the same graph paper,plot the speed versus time graphs for the two cars. Which ofthe two cars travelled farther after the brakes were applied?Fig 8 11 obou the diato

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12577.

30A cyclist is travelling at 15 m s-1. She applies brakes so that she does not collide with a wall 18 m away.What deceleration must she have ?

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12578.

A 1 Kg ball falls from a height of 25 cm andrebounds upto a height of 9 cm. The co-efficient ofrestitution is(1) 06 (2) 0.32 (3) 0.40(4) 0-56

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U = sqrt(2gH)= sqrt(2 × 9.8 × 0.25)

v = sqrt(2gh)= sqrt(2 × 9.8 × 0.09)

e = v / u= [sqrt(2 × 9.8 × 0.09)] / [sqrt(2 × 9.8 × 0.25)]= 0.6

Coefficient of restitution is 0.6

12579.

11. A body travelling with speed of 20 km/hr applies brakes and reduced to 10km/hr in 3 min. Calculate the acceleration of the body.

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Givenu = 20 km/ hv = 10 km/htime = 3 min. convert in hr. 3/60 =0.05 hr.solutionA =

A = v - u / t10 - 20 / 0.05 = -200 km/h

12580.

2. A body of mass 2 kg initially at rest moves under the action of an applied horizontal force of 7 N on atable with coefficient of kinetic friction-0.1. Compute the(a) work done by the applied force in 10s,(b) work done by friction in 10s,(c) work done by the net force on the body in 10 s,(d) change in kinetic energy of the body in 10 s, and interpret your resulisсеenCel

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12581.

πA man is at a height of 100 m. He sees a car which makes an angle of rad with man's00 m. He sces a car which makes an angle of rad with man'sposition. If the car moves to a point wherc angle is 3 rad, what is the distance moved by it?62100/3m(B) 200,3 m (O) 015013(D)m(A)

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12582.

A convex lens of focal length 20 cm can producea magnified virtual as well as real image. Is thisa correct statement? If yes, where shall the objectbe placed in each case for obtaining theseimages?5.9. 1el chemically? State the

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Yes, the statement is correct. A convex lens of focal length 20 cm will produce a magnified virtual image if object is placed at a distance less than 20 cm from the lens.A convex lens of focal length 20 cm will produce a magnified real image if object is placed at a distance greater than 20 cm and less than 40 cm from the lens

12583.

е 3. Define IJdjuo4. A pair of bullocks exerts a forceof 140 N on a plough. The fieldbeing ploughed is 15 m long.How much work is done inploughing the length of the field?

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12584.

Define work. Find an expression for amount of work done against force of friction when a body moves up an inclined plane.

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Work is said to be done when force applied on an object shows the displacement in that object.

W = F x s.

12585.

swer the following questions in detail.What are the different effects of force?

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Aforceacting on an object may cause the object to change shape, to start moving, to stop moving, to accelerate or decelerate. When two objects interact with each other they exert aforceon each other, the forcesare equal in size but opposite in direction.

12586.

6. Draw a diagram and apply the convention in the determination of focal length and nature of aspherical mirror which forms a times magnified virtual image of a object placed 18 cm in the front ofit.j(f = 9 cm)

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12587.

12) A convex mirror has a focal length of 18 cm. Tyimage of an object kept in front of the mirrorhalf the height of the object.What is the distance of the object from the min

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F=18O=x cm (let)I= x/2 cmwe have,I/O=v/uor, x/2x= v/uv= u/2again,1/f=1/u+1/v1/18= 1/u+2/uu=54cm Ans#

12588.

Define work done by a force. Explain the various types of work suitable examples.

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Workis said to bedonewhen an object moves (displaces) along the direction of application offorce." OR Theworkis defined asforcedisplacement. W = F x S

Types of workPositive workWhen a spring is stretched, the work done by the stretching force is positive as the force acts in the direction of displacement of the spring.

negative work The work done against friction is negative as the frictional force is always in direction opposite to displacement.

zero workA person carrying a load on his hand and walking on a horizontal road does no work as the force is acting at right angle to displacement.

12589.

Define work done by a force. Explain thevarious types of work with suitable examples.

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Work done by a force.Workisdonewhenever aforcemoves something over a distance. You can calculate the energy transferred, orwork done, by multiplying theforceby the distance moved in the direction of theforce. ... The transfer of energy is not 100% efficient and not all the energy transferred is represented by mgh

Special cases:

CaseI: When the body moves in the direction of the force. In this case, q = 0o.

from eq (i), we have

W = FScosoo

i.e. W = FS …(ii)

i.e. W = product of the force and the distance through which the body moves in the direction of the force.

This type of work is said to be positive. Therefore, work done by a force is positive is q < 90o

Examples of Positive Work:

(1) When a spring is stretched, the work done by the stretching force is positive as the force acts in the direction of displacement of the spring.

(2) When a body falls freely under gravity, the work done by gravity is positive as force (gravity) and displacement of the body are in the same direction.

(3) When a gas taken in a cylinder expands, work done by the force is positive as the displacement is in the direction of the force.

Case II:. When the force acting on a body and its displacement are in the opposite direction

In this case, q = 180o. Therefore, from eqn (i), we have

W = FS cos180o= FS(-1)

Or W = -FS …. (iii). This type of work is said to be negative. Therefore, work done by a force is negative if q > 90o.

Examples of Negative Work:

(i) The work done against friction is negative as the frictional force is always in direction opposite to displacement.

(ii) Work done in lifting a body is negative as gravitational force and displacement are in the opposite direction.

Case III:. When force and displacement are at right angle to each other.

In This case q = 90o

From eqn (i), we have

W = FS cos90o= FS . 0 = 0

Therefore, no work is done by a force which acts at right angle to the direction of displacement of the body.

Examples of Zero Work:

(i) The work done by the centripetal force acting on a body moving in a circle with uniform speed is zero as it is always at right angle to the direction of motion of the body.

W = FS cos90o

= FS (0)

= 0

(ii) A person carrying a load on his hand and walking on a horizontal road does no work as the force is acting at right angle to displacement.

Case IV: If S = 0, then from eqn. (i), we have

W = f x 0 x cosq = 0

Therefore, no work is done by because if it can not displace a body on which it acts.

12590.

5Explain the different types of cooling towers use

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Types of Cooling Towers1.Mechanical draft cooling tower.2.Atmospheric cooling tower.3.Hybrid draft cooling tower.4.Air flow-characterised cooling tower.5.Construction-characterised cooling tower.6.Shape characterized cooling tower.7.Cooling tower based on method of heat transferEach of these could carry several cooling towers. For instance, categorizing cooling towers in terms of heat transfer method gives three options: Dry cooling towers, Open circuit cooling towers and Closed circuit cooling towers/ fluid cooling towers.

12591.

Define corrosion. Explain in detail different types of corrosion.

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It is the process in which metals are slowly eaten up by the action of air moisture or chemicals. For example rusting is a form of corrosion in which iron is eaten up by the action of air and moisture and a reddish brown coating of iron oxide is formed as shown in the following chemical reaction.

1. Galvanic corrosionis the most common and impactful form of corrosion. It occurs when two dissimilar (different) metals are in contact in the presence of an electrolyte. In a galvanic cell (bimetallic couple), the more active metal (anode) corrodes and the more noble metal (cathode) is protected. There are a number of factors that affect the galvanic corrosion including types of metals, relative size of anode, and environment (temperature, humidity, salinity, etc.)

2. Microbial corrosion, commonly referred to as microbiologically influenced corrosion (MIC) is caused by microorganisms. It applies to both metallic and non-metallic materials with or without oxygen. When oxygen is absent, sulfate-reducing bacteria are active and produce hydrogen sulfide causing sulfide stress cracking. When oxygen is present, some bacteria may directly oxidize iron to iron oxides and hydroxides. Concentration cells can form in the deposits of corrosion products, leading to localized corrosion.

12592.

size4. An object of size 7.0 cm is placed at 27 cm in front of a concave minor of focallength 18 cm. At what distance from the mirror should a screen be placed, so thata sharp focused image can be obtained? Find the size and the nature of the Image

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12593.

2. A train ts trewelling nt a speeor 90 kmh Brakes are appliedso as to produce a uniformacceleration of 0.5 ms. Findhow far the train will go before itis brought to rest

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pls mark as the best

12594.

4. The Sun rises from the west and sets in the east on Venus. Do you agree with thisstatement? Why or why not?

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Unlike other planets inthe solarsystem that rotatewesttoeast(the same spinning direction ofthe Sunor prograde rotation),Venusspinseasttowest, (opposite tothe Sunor retrograde rotation). Hencethe sun riseflips in direction.

12595.

A 150 m long train is moving to north at aspeed of 10 m/s. A parrot flying towardssouth with a speed of 5m/s crosses the train.The time taken by the parrot to cross the trainwould be

Answer»

Distance to be covered by the parrot=150m

speed of train=10m/s

speed of parrot=5m/s

now consider the train with respect to parrot and not with respect to land.

velocity of parrot=5

velocity of train=-10(∵the train is in opposite direction)

so relative velocity of train w r t parrot = 5 - (-10)=15m/s

now time = distance/speed = 150/15= 10s

Like my answer if you find it useful!

12596.

A trolley of mass 200 kg moves with a uniform speed of 36 km/h on a frictionless track.A child of mass 20 kg runs on the trolley from one end to the other (10 m away) with aspeed of 4 m s' relative to the trolley in a direction opposite to the its motion, andJumps out of the trolley. What is the final speed of the trolley? How much has thetrolley moved from the time the child begins to run?

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12597.

Examplebased onDependence of RangeIn broad jumping does it matter how high youjump ? What factors determine the span of theJump?(1) Yes, u &amp; θ(3) No, h &amp; eEx.10(2) No, u &amp; θ(4) of these

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12598.

13.Atmospheric pressure recorded by simple barometer is 75 cm of mercury. The atmosphericpressure in Pascal is: (g 9.8 m/s)1) 99900 Pa 2) 99990 Pa3) 99960 Pa4) 99999 Pa

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75 Centimeter Mercury (0°C) (cmHg)

=

99991.77632 Pascal (Pa

12599.

Ex.A train goes from station A to station B as shown in figure. Calculateo the distance travelled by the train andW the magnitude of the displacement of the train on reaching station B.Station A50 km...100 kmm......Station BRailway track400 kn150 km

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the distance travelled by train=50+100+200+400=750kmthe magnitude of displacement = 400km

12600.

A strip of flexible plastic with magnetic coating that is used to record sound and pictures.

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Magnetic Tape