ÙetLe keâe@efcheefšMeve šeFcme

ISRO Technical Assistant

Mechanical Engineering

hejer#ee %eeve keâesMe efJemle=le JÙeeKÙee meefnle nue ØeMve-he$e mebheeove SJeb mebkeâueve ISRO hejer#ee efJeMes I2 E1 < E 2 5

Ans : (c) yee@ue

efyeÙeeEjie meeceevÙeleÙee ›eâesce Fmheele kesâ yeveeS peeles nQ~ yee@ue efyeÙeeEjie– FmeceW Skeâ Fvej jsme neslee nw pees Meeheäš Ùee pevejue hej ceeGbš neslee nw~ leLee otmeje DeeGšj jsme neslee nw pees neGefpebie Ùee kesâefpebie Éeje ues peeÙee peelee nw~ Fvej jsme leLee DeeGšj jsme kesâ yeerÛe Skeâ efveef§ele otjer efjšsvej kesâ Éeje Øeehle keâjles nw pees oesveeW keâes he=Lekeâ jKeles nw Deewj efjšsvej Skeâ heleueer heóer nesleer Ùen oes YeeieeW ceW neslee nw~ Skeâ cesue leLee otmeje heâercesue heeš& neslee nw~ Fve oesveeW heešeX keâer meneÙelee mes yee@ue keâes efveef§ele mLeeve ceW meceefvJele keâjles nw~ yee@ue efyeÙeefjbie keâe ØeÙeesie nukesâ YeejeW nsleg leLee jesue efJeÙeefjbie keâe ØeÙeesie Yeejer YeejeW kesâ efueS ØeÙeesie neslee nw~ yee@ue efyeÙeefjbie meeOeejCeleÙee ›eâesce Fmheele Ùee ceOÙece keâeye&ve Fmheele kesâ yeveeÙes peeles nw~

8.

The most efficient section of a flow channel is :

ØeJeen Jeeefnkeâe keâe meyemes ØeYeeJeer KeC[ .......... nw~ (a) circular/Je=òeerÙe (b) rectangular/mecekeâesCeerÙe (c) square/Jeie& (d) trapezoidal/meceuecye Ans : (d) ØeJeen Jeeefnkeâe keâe meyemes ØeYeeJeer KeC[ meceuecye nw~ veesš– DeefOekeâlece efceleJÙeÙeer meceuecyeekeâej keâeš kesâ efueS efvecve yeeleW ueeiet nesleer nQ~ (a) Ûewveue keâeš keâer meeF[ Yegpee õJe leue ÛeewÌ[eF& keâer DeeOeer nesleer nw~ meeF[ Yegpee keâer uecyeeF& = (b)

õJe-leue ÛeewÌ[eF& 2

õJeerÙe ceeOÙeceeve ienjeF& keâeš keâer ienjeF& keâer DeeOeer nesleer nw~ m =

7.

h 2

Charpy test is conducted to measure : (c) õJe-leue kesâ ceOÙe efyevog keâes kesâvõ ceevekeâj KeeRÛee ieÙee DeOe& Je=òe Ûeeheea efvekeâ tan α ⇒ µ > tan α

(∵ tan φ = µ ) 14

ef[peeFve, nthe Øeefleyeue keâes DeeOeej ceevekeâj efkeâÙee

⇒

t=

Pd 2 × σh

⇒

t=

9 × 500 2 × 180

⇒

t=

225 = 12.5mm 18

⇒

t = 12.5mm

35.

In a close-coiled helical spring subjected to an Ans : (d) axial load other quantities remaining the same, ieÙeer, #eweflepe if the wire diameter is doubled, then the stiffness of the spring when compared to the Jen 45º nw~ original one will become :

Skeâ ieesueer DeefOekeâlece hejeme lekeâ hengBÛeeves nsleg ÛeueeF& kesâ mecyevOe ceW, θ keâesCe efpeme hej Fmes heâeÙej keâjvee nw

DevÙe meYeer cee$eeDeeW keâes meceeve jKeles ngS mebJe=òe kegâC[efuele keâceeveer keâes De#eerÙe Yeej kesâ DeOeerve efkeâÙee peelee nw, Ùeefo JeeÙej kesâ JÙeeme keâes ogiegvee efkeâÙee peelee nw, lees cetue kesâ meeLe Fmekeâer leguevee keâjves hej keâceeveer/eEmØeie keâer ogve&cÙelee ........... nes peeSieer~ (a) twice/ogiegvee ⇒ Ùeefo (b) four time/Ûeewiegvee (c) eight times/Dee" iegvee (d) sixteen times/meesuen iegvee ∵

Ans : (d) ØeMveevegmeej– d1 = d, d2 = 2d,

R1 = R2 = R n1 = n2 = n

peneB–

C1 = C2 = C

C → keâle&ve

keâesCe, Rmax → DeefOekeâlece hejeme u → ØeejefcYekeâ Jesie hejeme (R) =

∵

d→

∴

k ∝ d4

n → šveeX

⇒

k1  d1  =  k2  d2 

∵ DeefOekeâlece #eweflepe hejeme nsleg– sin 2θ = 1 sin 2θ = sin 900

ceeheebkeâ

∵

d1 = d, d2 = 2d

leej keâe JÙeeme

∴

keâer mebKÙee

θ = 45º

R max =

u 2 sin(2 × 45) g

R max =

u2 g

4

....(i)

4

u 2 sin 2θ g

2θ = 900

Cd 4 k= 64R 3 n

k→

efmØebie ogve&cÙelee

∴

keâe ceeve meceerkeâjCe (1) ceW jKeves hej–

k1  d   1  =  =  k 2  2d   2 

37.

4

Bending moment at a hinge is :

eEnpe ceW yebkeâve DeeIetCe& ........... nw~ (a) 0

k1 1 = k 2 16 ∴

θ → Øe#eshÙe

(b) Maximum/DeefOekeâlece (c) Minimum/vÙetvelece

k 2 = 16k1

(d) Depends on the loading/Yeej hej DeeOeeefjle nw DeLee&led Ùeefo leej keâe JÙeeme oesiegvee keâj efoÙee peeS, lees efmØebie ogve&cÙelee Ans : (a) efnvpe hej yebkeâve DeeIetCe& MetvÙe neslee nw~ 16 iegvee nes peeÙesieer~

36.

A bullet is fired to get maximum range. the angle θ at which it is to be fired (neglecting drag in air) with respect to the horizontal is :

38.

A hydraulic turbine develops 1000 kW power for a head of 40 m. If the head is reduced to 20 m, the power developed (in kW) is :

Skeâ ieesueer DeefOekeâlece hejeme lekeâ hengBÛeeves nsleg ÛeueeF& ieF&~ #eweflepe kesâ mecyevOe ceW, θ keâesCe efpeme hej Fmes heâeÙej keâjvee nw (JeeÙeg ceW Fmekesâ keâ