PHYSICS GALAXY PG Brainstormer - 2H (Solutions) PG Brainstormer - 2 H RECTILINEAR MOTION, PROJECTILE & 2D MOTION & RELATIVE MOTION An Ultimate Tool to understand advanced High School Physics by ASHISH ARORA Sir Time Allowed 90 Min Maximum Marks 110 SOLUTIONS 1. Ans. (B) V C = 4 kph V RC = 3 kph V RC V C V R RC V = R C V V R V = RC C V V V R = 2 2 RC C V V = 5 kph 2. Ans. (A) r = 0 r + Vt = ˆ ˆ ˆ ˆ ˆ ˆ (3 2) ( 3) 3 i j k i j k = ˆ ˆ 2 7 j k 3. Ans. (B) Distance travelled by A is = 20 + 1 2 × 10 × 6 = 50 m Distance travelled by B is = 30 + 1 2 × 10 × 5 = 55 m V avg A = 50 8 = 6.26 m/s V avg B = 55 7 = 7.85 m/s 4. Ans. (C) RG V = R G V V V RG –V G V R V RG = 2 2 3 4 = 5 kph 5. Ans. (A) Time to cross for bullet t = 2 ( cos 10) V = 3 sin V 3m 10 m/s 2m V tan = 3/4 2V sin = 3V cos – 30 3 2 5 V = 4 3 5 V – 30 6V = 12 V – 150 6V = 150 V = 25 m/s t = 3 3 25 5 = 3 5 3 = 1 5 = 0.2 sec
PHYSICS GALAXYPG Brainstormer - 2H (Solutions)PG Br ai nst or
mer- 2 HRECTILINEAR MOTION, PROJECTILE & 2D MOTION &
RELATIVE MOTIONAnUltimateTool tounderstandadvancedHigh School
Physics by ASHISH ARORASirTime Allow ed 90 M inM aximum Marks
110SOLUTI ONS1. Ans. (B)VC =4 kphVRC =3 kphVRCVCVRRCV= R CV VRV=RC
CV V + VR =2 2+RC CV V=5 kph2. Ans. (A)r =0r+Vt= (3 2 ) ( 3 ) 3 + +
+ + i j k i j k= 2 7 j k3. Ans. (B)Distance travelled by A is =20
+12 10 6 =50 mDistance travelled by B is =30 +12 10 5 =55 mVavg A
=508 =6.26 m/sVavg B =557 =7.85 m/s4. Ans. (C)RGV= R GV VVRGVGVRVRG
=2 23 4 +=5 kph5. Ans. (A)Time to cross for bullett =2( cos 10) u V
=3sinu V3m10 m/s2mVtan=3/42V sin u =3V cos u 30325| | |\ .V=435| |
|\ .V 306V =12 V 1506V =150V =25 m/s t =33255 =35 3 =15 =0.2
secPHYSICS GALAXYPG Brainstormer - 2H (Solutions)6. Ans. (B)VM =4
kphRMV= R MV VVRMVMVRVR is +RV= + RM MV Vu =tan1 MRMVV =tan1 13
=307. Ans. (A)To hit the monkey minimum V0 is such that2Hg =2 20+ H
LVV0 =2 2( )2+gH LH8. Ans. (A)With respect to motorcycle, car
should travel such that100 =22Va a =2200V =400200 =2 m/s29. Ans.
(A)For shortest time man should swim normal to river current.10.
Ans. (B)VR10 m/sVG8 m/sVRGVRVGV RGG=V VRUsing sine rulesin2t | ||
|\ .RV =sin( ) | oBV10 [sin | cos o cos | sin o] =8 cos |10 tan |
cos o 10 sin o =8tan | =8 10sin10cos+ oo11. Ans. (A)PHYSICS
GALAXYPG Brainstormer - 2H (Solutions)VA5 kphVBE30NVAVBVBA30V
BABA=V V is VB sin 30 =5VB =10 kph12. Ans. (B)Range =2sin2 ugu
=2(20)10 =40 mtime to flight t =2 sin ugu =12 20210 =2 2 secSpeed
of B =302 2 =7.5 2 m/s13. Ans. (D)If river current speed is u 50
=1004v uVto reach point B the angle to bank at which he should swim
iscos u =uv =12u =60 upstream14. Ans. (A)VP =500 kphBC300 km1000
kmAPGV=P WV V + As AB =500 2 =1000 kmBC =VW 2 =300 kmVW =150 km
NE15. Ans. (C)Vr =5 m/minVs =10 m/minin figureu =sin1 rsVV =sin1
12| | |\ . =30VsVrNE16. Ans. (A)PHYSICS GALAXYPG Brainstormer - 2H
(Solutions)T0 =2PlVTW =P W P Wl lV V V V++ =2 22PP WlVV V TW
>T017. Ans. (C)90 90 VuBAs shown in figure angle between uand
vis 180 2u.18. Ans. (A)At the point of hitH =2 2sin2u ug =l sin |
(1) lu2R =22 sin cos2u u ug =l cos | (2)(1) (2)tan2u =tan | tan u
=2319. Ans. (D)VM =10 2 m/s (NE)eMV=e MV VVe =20 m/s (East)from
figure u =45VWVM VWM4520. Ans. (C)W.r. to second truck moving at
same speed of first truck path will be a vertical straight line and
in all other three caseswill be a parabola.21. Ans. (A, B, D)If
wind blows along line ABT1 =0 0++ l lV V V V =02 202lVV VIf wind
blows to ABT2 =2 2 2 20 0+ l lv v v v = 2 202lv vPHYSICS GALAXYPG
Brainstormer - 2H (Solutions)If no windT3 =02lv (T3
