Tiêu đề 2. KINEMATICS_VOL-2_KEY _ SOLUTIONS (19-29).pmd.pdf ✅

VIII – Physics (Vol – II) 19 Narayana Group of Schools Olympiad Class Work Book KINEMATICS PART - II WORKSHEET--5 KEY & SOLUTIONS CUQS: 1) 2 2) 1 3) 3 4) 3 5) 2 6) 1 7) 3 8) 4 9) 4 JEE MAINS & ADVANCED : 1) 4 2) 1 3) 2 4) 3 5) 4 6) 2 7) 1 8) 2 9) 1 10) 2 11) 3 12) 4 13) 2 14) 4 15) 1 16) 4 17) 2 18)4 19) 1,2,3 20) 4 21) 4 22) 1 23) a- q; b- p; c- r; d-s 24) 25 25) a- q; b- p; c- r; d-s 26) 1 27) 1 28) 1 29) 1 30) 1 31) 2 32) 1 JEE MAINS & ADVANCED 1. North 2. VWG  VMG  VMW  V 5m/min WG   V 10m/min MW   from fig WG MW V sin V   5 sin 10   1 sin 2   sin sin30   30 W of N    3. V = 4 WG m/min  VMG  V = 10 MW m/min  d = 5 0 0 m Form the figure MW widthof theriver time V  500m t 10m/min  t 50min  4. VWG = 5 kmph VMG  V = 10 MW m/min Form figure 2 2 V V V MG MW WG   2 2   10 5  125 V 5 5 MG  kmph
Olympiad Class Work Book VIII – Physics (Vol – II) 2 2 2 2 V V V kmph b bw w      13 5 12 5 tan 12 w b V V    1 5 tan 12 W of N          8. The boat travels 16 km in 2 hours in still water  Velocity of boat, 16 2 b km V hr   8 / km hr velocity of river flow, v km hr r  4 / velocity of boat in down stream =V V km hr b r     8 4 12 / Time taken by the boat to cover a dis- tance 8 km in downstream is to 8 2 12 3 km hr km hr  velocity of boat in up- stream=V V km hr b r     8 4 4 / Time taken by the boat to cover a dis- tance 8 km in upstream is 8 2 4 u km T hr    Total time of travel 2 2 2 40min 3 D U t t hr hr            9. 1 10 d t v     d v 10 x ut  1    120 10 u 1 12 min m u    5. VWG = 6 kmph VMG V  = 10 MW m/min 1 km  From figure 2 2 V V V MG MW WG    2 2   10 6   100 36  64 V kmph MG  8   time taken to cross the river width 1 km is MG width t V   1 8 t hr  6. Given time t hr 1 12 t hr 2  8 Distance between two points in river is same. 1 2 1 2 2t t t t t    2 12 8 12 8 t     48 5 t  t hr  9.6 7. From figure N E  vb  vbw  vw 