Tiêu đề 5. P1C5 (Work, Energy and Power) With Solve.pdf ✅

KvR, kw3 I ÿgZv  Varsity Practice Sheet ..................................................................................................................... 1 weMZ mv‡j DU-G Avmv cÖkœvejx 1. 10g-Gi GKwU fi Nl©Ynxb GKwU Abyf‚wgK Z‡ji Ici w`‡q wM‡q †`qv‡ji mv‡_ mshy3 GKwU Abyf‚wgK w ̄úas‡K 6m/s †e‡M AvNvZ K‡i| hw` w ̄úaswUi w ̄úas aaæe‡Ki gvb 400 N/m nq Zvn‡j GwU‡Z m‡e©v”P ms‡KvPb KZ n‡e? [DU 23-24] 0.3 cm 3 10 cm 3 cm 0.9 m DËi: 3 cm e ̈vL ̈v: 1 2 mv2 = 1 2 kx2  x = mv2 k = 10–2 400  6 = 3cm 2. GKwU KYv t = 0 mg‡q w ̄’i Ae ̄’v †_‡K hvÎv ïiæ K‡i| KYvwUi Ici cÖhy3 jwä ej, mgq t Gi mgvbycvwZK| KYvwUi MwZkw3 wb‡Pi †KvbwUi mgvbycvwZK n‡e? [DU 22-23] t 2 t 3 t t 4 DËi: t 4 e ̈vL ̈v: F  t  a  t a = kt  dv dt = kt  dv = ktdt  v = kt2 2  v  t 2 Ek = 1 2 mv2 Ek  t 4 3. GKwU ivevi e ̈vÛ‡K †U‡b Gi ˆ`N© ̈ x cwigvY e„w× Ki‡j, ivevi e ̈v‡Û cÖZ ̈veZ©x ej n‡jv F = ax + bx2 (GLv‡b a Ges b aaæeK)| ivevi e ̈vÛwU‡K x = 0 †_‡K x = L ch©šÍ e„w× Ki‡Z K...Z Kv‡Ri gvb KZ? [DU 21-22] aL2 + bLx3 aL2 2 + 2bL2 a + 2bL aL2 2 + bL3 3 DËi: aL2 2 + bL3 3 e ̈vL ̈v: W = Fdx =  0 L (ax + bx2 ) dx =     ax2 2 + bx3 3 L 0 = aL2 2 + bL3 3 4. GKwU m f‡ii e ̄‘ Nl©Ywenxb GKwU Z‡j v †e‡M Pjvi mgq GKwU w ̄úas-Gi mv‡_ av°v †j‡M w ̄úaswU‡K msKzwPZ Kij| w ̄úaswUi ej-aaæeK k n‡j| w ̄úaswU KZUzKz msKzwPZ n‡e? [DU 20-21] m k v k m v kv mv DËi: m k v e ̈vL ̈v: 1 2 kx2 = 1 2 mv2  x = mv2 k = v m k 5. 30 m D”PZv †_‡K GKwU e ̄‘‡K webv evavq co‡Z w`‡j †Kvb D”PZvq e ̄‘wUi MwZkw3 wefekw3i wØ ̧Y n‡e? [DU 16-17] 10 m 15 m 25 m 28 m DËi: 10 m e ̈vL ̈v: Ek = 2Ep  30 – x = 2x  x = 10 m 6. hw` 60 kg IR‡bi GKwU †jvK 4 m ˆ`‡N© ̈i GKwU †`vjbvq e‡m 3 m we ̄Ív‡i `yj‡Z _v‡K, Zvn‡j †jvKwUi m‡e©v”P MwZkw3 KZ n‡e? [DU 16-17] 660 J 680 J 700 J 720 J DËi: Blank e ̈vL ̈v: Ekmax = Epmax = mgl (1 – cos) = 60  9.8  4     1 – 4 2 – 3 2 4 = 796.2982 J  4 m 3 m
2 .........................................................................................................................................  Physics 1st Paper Chapter-5 7. GKwU cvwbc~Y© Kzqvi MfxiZv 12 m Ges e ̈vm 1.8 m| GKwU cv¤ú 24 wgwb‡U KzqvwU‡K cvwbk~b ̈ Ki‡Z cv‡i| cvwbi NbZ¡ 1000 kgm–3 n‡j cv¤úwUi ÿgZv KZ? [DU 16-17] 1.67 HP 3.34 HP 6.68 HP 26.72 HP DËi: 1.67 HP e ̈vL ̈v: havg = me©wb¤œ MfxiZv + m‡e©v”P MfxiZv 2 = 12 + 0 2 = 6 m = V = r 2 h = 1000  3  (0.9)2  12 = 3000  0.81  12 P = mghavg t = 3000  0.81  10  6  12 24  60  3000  0.8  12 24  1200 W  1200 750  120 75  24 15  1.6 HP KvQvKvwQ Option 1.67 HP 8. 1 g f‡ii GKwU e ̄‘‡K 0.5 m e ̈vmv‡a©i GKwU Avbyf‚wgK e„ËvKvi c‡_ 2 ms–1 mg`aæwZ‡Z †Nviv‡bv n‡”Q| GKwU c~Y© N~Y©‡bi Rb ̈ cÖ‡qvRbxq Kv‡Ri gvb KZ? [DU 15-16] 0 J 1 J 2 J 4 J DËi: 0 J e ̈vL ̈v: †K›`agyLx ej Øviv K...ZKvR k~b ̈| 9. †Kvb e ̈w3 30 Xv‡ji 5 m DuPz NlY©wenxb Zj eivei GKwU 100 N eøK †U‡b Zzj‡Q| eøKwU mg`aæwZ‡Z Pj‡j e ̈w3 Kx cwigvY KvR Ki‡e? [DU 14-15] 250 J 500 J 800 J 100 J DËi: 500 J e ̈vL ̈v: 30 5m W = mgh = 100  5 = 500 J 10. GKwU ey‡jU GKwU Kv‡Vi Z3v †f` Ki‡Z cv‡i| ey‡jUwUi MwZ 4 ̧Y e„w× Ki‡j Bnv KqwU H GKB gv‡ci Z3v †f` Ki‡Z cvi‡e? [DU 13-14; CU 10-11; KU 09-10, 05-06] 12 9 8 16 DËi: 16 e ̈vL ̈v: N = x 2 n  N = 16  1  N = 16 11. wP‡Î †`Lv‡bv c_ w`‡q GKwU 4.0 N IR‡bi cv_i‡K AwfKl©xq †ÿ‡Î P we›`y †_‡K R we›`y‡Z ̄’vbvšÍwiZ Kiv nj| cv_iwUi w ̄’wZkw3 KZ e„w× †cj? [DU 13-14] 40 m R Q 30 m 50 m P Earth’s surface 120 J 200 J 280 J 1200 J DËi: 120 J e ̈vL ̈v: AwfKl© ej GKwU msiÿYkxj ej nIqvq y Aÿ eivei miYB n‡jv h W = mgh = 4  30 = 120 J 12. 100 kg f‡ii GKwU e ̄‘i fi‡eM 200 kgms–1 n‡j Gi MwZkw3 KZ? [DU 08-09] 400 J 300 J 200 J 100 J DËi: 200 J e ̈vL ̈v: Ek = p 2 2m = (200) 2 2  100 = 400 2 = 200 J weMZ mv‡j GST-G Avmv cÖkœvejx 1. cÖwZ †m‡K‡Û 10 wj. cvwb 10 m Dc‡i †Zvjvi Rb ̈ KZ ÿgZvi cv¤ú cÖ‡qvRb n‡e? [GST 23-24] 980 J 998 J 980 W 998 W DËi: 980 W e ̈vL ̈v: P = mgh t = 10 × 9.8 × 10 1 W  P = 980 W 2. 250 m DuPz GKwU SY©v †_‡K cvwb gvwU‡Z c‡o Avbyf‚wgKfv‡e wbw`©ó MwZ‡e‡M Mwo‡q hv‡”Q| kw3i AcPq AMÖvn ̈ Ki‡j cvwbi †eM KZ? [GST 23-24] 100 ms–1 90 ms–1 80 ms–1 70 ms–1 DËi: 70 ms–1 e ̈vL ̈v: mgh = 1 2 mv2  v = 2gh = 2 × 9.8 × 250 ms–1 = 4900 ms–1  v = 70 ms–1
KvR, kw3 I ÿgZv  Varsity Practice Sheet .................................................................................................................... 3 3. 200 g f‡ii GKwU e ̄‘ 20 m Dci †_‡K co‡j f~wg ̄úk© Kivi c~e© gyn~‡Z© MwZkw3 KZ n‡e? [GST 23-24] 3.92 J 39.2 J 9.8 J 98 J DËi: 39.2 J mgvavb: Ek = Ep = mgh  0.2  10  20  40 L Option me‡P‡q KvQvKvwQ| 4. w ̄’ive ̄’v †_‡K 20 kg f‡ii †Kv‡bv e ̄‘ GKwU wbw`©ó e‡ji wμqvi d‡j 3 s c‡i 6 ms–1 †eM AR©b Ki‡j 5 s ci Gi MwZkw3 KZ kJ? [GST 22-23] 3 2 1 0.5 DËi: 1 e ̈vL ̈v: v = u + at  6 = 0 + a  3  a = 2 ms–2 5 s ci v = at = 2  5 = 10 ms–1 E = 1 2 mv2 = 1 2  20  102 = 1000 J = 1 kJ 5. 500 g f‡ii GKwU KYvi Dci (6x2 – 4x) N ej wμqv Kivq e ̄‘wU e‡ji w`‡K x = 0 Ae ̄’vb n‡Z x = 2 Ae ̄’v‡b m‡i †M‡j e‡ji Øviv K...ZKv‡Ri cwigvY KZ J? [GST 22-23] 8 6 4 2 DËi: 8 e ̈vL ̈v: W =  2 0 (6x2 – 4x) dx =     2x3 – 4x2 2 0 2 = 16 – 2  4 = 8 J 6. msiÿYkxj ej Øviv 1 kg f‡ii GKwU e ̄‘‡K A †_‡K B we›`y‡Z †bqv n‡jv Ges B †_‡K A we›`y‡Z wdwi‡q Avbv n‡jv| e ̄‘wUi Dci KZ J KvR Kiv n‡jv? [GST 21-22] 1 0 0.5 2 DËi: 0 e ̈vL ̈v: msiÿYkxj ej Øviv c~Y© P‡μ K...ZKvR 0| 7. v1 †e‡Mi GKwU ey‡jU ïaygvÎ wbw`©ó cyiæ‡Z¡i GKwU Z3v †f` Ki‡Z cv‡i| Giƒc bqwU Z3v †f` Ki‡Z n‡j H ey‡j‡Ui †eM KZ n‡Z n‡e? [GST 21-22] 2v1 4v1 5v1 3v1 DËi: 3v1 e ̈vL ̈v: v0 †e‡M n wU Z3v †f` Ki‡Z cvi‡j, xv0 †e‡M N = x2 n msL ̈K Z3v †f` Ki‡Z (†eM‡K x ̧Y Ki‡j) cv‡i| n = 1, N = 9 9 = 1  x 2  x = 3 8. GKwU `vjv‡bi Qv‡`i mv‡_ jvMv‡bv 10 m j¤^v GKwU gB f‚wgi mv‡_ 30 †Kv‡Y AvbZ Av‡Q| 68 kg f‡ii GK e ̈w3 12 kg f‡ii wRwbmmn 19.6 s G gB †e‡q Qv‡` D‡V| H e ̈w3 KZ IqvU (W) ÿgZv cÖ‡qvM Ki‡Q? [GST 20-21] 200 300 400 600 DËi: 200 e ̈vL ̈v: 10m 30 10 sin30 Total mass = (68 + 12) = 80 kg P = mgh t = 80  9.8  10 sin30 19.6 = 40  5 = 200 W weMZ mv‡j Agri-G Avmv cÖkœvejx 1. Kv‡Ri AwfKl©xq GKK Kx? [Agri. Guccho 21-22] kgm Nm Nm2 kgm2 DËi: kgm e ̈vL ̈v: Kv‡Ri AwfKl©xq GKK = Kv‡Ri GKK AwfKl©R Z¡i‡Yi GKK = Nm ms–2 = kgms–2 m ms–2 = kgm 2. GKwU †gvUi GKwU 120 m Mfxi K‚c †_‡K 5 wgwb‡U 400 kg cvwb D‡Ëvjb Ki‡Z cv‡i| †gvUiwUi ÿgZv KZ? [Agri. Guccho 21-22] 3 HP 2.8 HP 2.5 HP 2.1 HP DËi: 2.1 HP e ̈vL ̈v: P = W t = mgh t = 400  10  120 5  60 = 1600 W  1600 750 HP  32 15 HP  30 15 HP  2 HP
4 .........................................................................................................................................  Physics 1st Paper Chapter-5 3. GKwU ivB‡d‡ji ̧wj GKwU Z3v‡K †f` K‡i| ey‡j‡Ui MwZ hw` wZb ̧Y Kiv nq, Z‡e ey‡jUwU KqwU Z3v †f` Ki‡Z cvi‡e? [Agri. Guccho 20-21; JU 14-15] 3 12 8 9 DËi: 9 e ̈vL ̈v: N = x2 n  N = 32  1  N = 9 weMZ mv‡j JU-G Avmv cÖkœvejx 1. Kv‡Ri gvÎv †KvbwU? [JU 22-23] MLT–2 ML2L 2 ML2T –2 ML–2T –2 DËi: ML2T –2 2. hw` fi A‡a©K Ges †eM wØ ̧Y Kiv nq Z‡e MwZkw3 n‡e c~‡e©iÑ [JU 22-23] mgvb A‡a©K wØ ̧Y Pvi ̧Y DËi: wØ ̧Y e ̈vL ̈v: Ek2 = 1 2  m 2  (2v)2 = 2  1 2 mv2 = 2Ek1 3. †Kv‡bv MwZkxj e ̄‘i †eM 2 ms–1 Ges MwZkw3 1 J n‡j, e ̄‘i fi n‡eÑ [JU 22-23] 0.5 kg 1 kg 1.5 kg 2 kg DËi: 0.5 kg e ̈vL ̈v: Ek = 1 2 mv2  1 = 1 2 m  (2)2  m = 1 2 kg 4. 400 kg I 1 m e ̈vmv‡a©i GKwU wb‡iU †MvjK 2 ms–1 †e‡M Mwo‡q Pj‡j, Gi MwZkw3 KZ? [JU 22-23] 2120 J 1150 J 1120 J 2150 J DËi: 1120 J e ̈vL ̈v: wb‡iU †Mvj‡Ki Rb ̈, Total kinetic energy = 1 2 mv2 + 1 2 I 2 = 1 2 mv2 + 1 2  2 5 mr2  v 2 r 2 = 7 10 mv2 Ek = 7 10  400  2 2 = 7 10  400  4 = 7  160 = 1120 J 5. ÿgZvi GKK †KvbwU? [JU 22-23] Ryj IqvU Ryj-†m‡KÛ AvM© DËi: IqvU 6. GKwU N~Y©vqgvb e ̄‘i fi 2 kg| N~Y©b Aÿ n‡Z Gi `~iZ¡ 1 m| e ̄‘wU 5 rads–1 †KŠwYK †e‡M Nyi‡j MwZkw3 KZ n‡e? [JU 21-22] 25 J 12.5 J 50 J 100 J DËi: 25 J e ̈vL ̈v: Ek = 1 2 I 2 = 1 2 mr2 2 = 1 2  2  1 2  25 = 25 J 7. ej I mi‡Yi ga ̈eZ©x †KvY  n‡j FYvZ¥K Kv‡Ri kZ© n‡eÑ [JU 21-22] 180    90 180   > 90 180    90 180 >   90 DËi: 180   > 90 8. GKwU KYvi Ici F  = (5i )  + 3j  – 6k  N ej cÖ‡qvM Kivq KYvwU X-Aÿ eivei 10 m m‡i †Mj| KYvi Dci K...ZKvR KZ? [JU 21-22] 30 J 50 J –60 J 15 J DËi: 50 J e ̈vL ̈v: W = F  .r  = (5i )  + 3j  – 6k  .10i  = 50 J 9. 50 N IR‡bi GKwU e ̄‘‡K 6 m D”PZvq DVv‡bvi R‡b ̈ GKwU wjdU e ̈envi Kiv n‡jv| GwU 70 J kw3 e ̈q K‡i| AcPqK...Z kw3i cwigvY KZ? [JU 21-22] 230 J 12.5 J 300 J 100 J DËi: 230 J e ̈vL ̈v: AcPq = 50  6 – 70 = 230 J 10. †Kv‡bv e ̄‘ 20 m D”PZv †_‡K webv evavq co‡j, f‚wg n‡Z KZ D”PZvq MwZkw3 wefekw3i wZb ̧Y n‡e? [JU 21-22] 5 m 10 m 15 m 20 m DËi: 5 m e ̈vL ̈v: mg (h – x) = 3mgx  h – x = 3x  h = 4x  x = 5 m