Tiêu đề 5. P1C5.-Work-Power__With Solve.pdf ✅

KvR, kw3 I ÿgZv  Mastery Practice Sheet 1 cÂg Aa ̈vq KvR, kw3 I ÿgZv Work, Energy and Power weMZ eQ‡i BwÄwbqvwis fvwm©wU‡Z Avmv wjwLZ cÖkœmg~n 1| 0.5 kg f‡ii KvV LÐ Lvov Zj †N‡l co‡Q| Nl©Y ̧Yv1⁄4 0.25| Djø¤^ w ̄úas‡qi mv‡_ msNl© n‡q 4 m w ̄úas msKzwPZ nq| msN‡l©i mgq KvV L‡Ði †eM wbY©q Ki| [w ̄úas aaæeK = 4.8 Nm–1 ]| [BUET 22-23] mgvavb: kw3i wbZ ̈Zv n‡Z, 1 2 kx2 = 1 2 mv2 + mgx  1 2 × 4.8 × 42 = 1 2 × 0.5 × v2 + 0.5 × 9.8 × 4  v = 8.671 ms–1 (Ans.) 2| gvby‡li nvU© cÖ‡Z ̈K we‡U 10 cm(Hg) Pv‡c 75 cc i3 mÂvjb K‡i| cvjm †iU cÖwZ wgwb‡U 80 wU a‡i nv‡U©i ÿgZv †ei Ki| cvi‡`i NbZ¡ 13.6 g/cc| [BUET 21-22] mgvavb: P = W t = PV t = hg. V t = 10  10–2  13600  9.8  75  10–6 60 80 Watt = 1.3328 Watt. (Ans.) 3| †KvwfW-19 (COVID-19) AwZgvix mg‡q 4  103 kg f‡ii GKwU wcKAvc UavK Ges 103 kg f‡ii GKwU gvB‡μvevm Aw·‡Rb wmwjÛvi mieiv‡ni Rb ̈ GKwU nvmcvZv‡j hvw”Qj| wcKAvc Uav‡Ki †eM NÈvq 80 km wQj| GKB MwZkw3 m¤úbœ n‡Z n‡j gvB‡μvevm‡K KZ †e‡M Pj‡Z n‡e? [BUET 20-21] mgvavb: EkP = EkT  1 2 mPv 2 P= 1 2 mTv 2 T  4  103  v 2 P = 103  (80)2  vP = 40 kmh–1 (Ans.) 4| †Kv‡bv Kzqv †_‡K 30 m Dc‡i cvwb †Zvjvi Rb ̈ 5 kW Gi GKwU cv¤ú e ̈envi Kiv nq| cv‡¤úi Kg©`ÿZv 90% n‡j cÖwZ wgwb‡U KZ wjUvi cvwb †Zvjv hv‡e? [g = 9.8 ms–2 ] [BUET 18 – 19] mgvavb: Pt = mgh  (5  103  0.9)  60 = m  9.8  30  m = 918.37 g V = m  = 918.37 1 L = 918.37 L (Ans.) 5| 1 wU †μb cÖwZwU 50 kg IR‡bi 12 wU wm‡g‡›Ui e ̈vM mg`aæwZ‡Z 160 m DuPz GKwU wbg©vbvaxb fe‡bi Qv‡` IVv‡Z 1 min 10 sec mgq †bq| †μbwUi ÿgZv Ak¦kw3‡Z †ei Ki| [BUET 17-18] mgvavb: Avgiv Rvwb, ÿgZv, P = Fv GLv‡b, F = Nmg = 12  50  9.8 N = 5880 N v = s t = 160 m 70s = 16 7 ms–1 myZivs, wb‡Y©q P = Fv = 5880  16 7 W = 13440 W = 13440 746 HP = 18.02 HP (Ans.) 6| 3 kg f‡ii e ̄‘i Dci GKwU ej wμqvkxj Av‡Q| e ̄‘wUi Ae ̄’v‡bi mgxKiY x = 3t – 4t2 + t3 , †hLv‡b x Gi gvb wgUv‡i Ges t Gi gvb †m‡K‡Û| t = 0 n‡Z t = 4 †m‡KÛ mg‡q ejwU w`‡q e ̄‘i Dci K...ZKv‡Ri cwigvY wbY©q K‡iv| [BUET 16-17] mgvavb: x = 3t – 4t2 + t3 v = 3 – 8t + 3t2 t = 0s G v0 = 3 ms–1 t = 4s G v4 = 19 ms–1  W = Ek = 1 2  3  (192 – 3 3 ) = 528 J (Ans.) 7| GKwU BwÄb 200 m Mfxi K‚c †_‡K cÖwZ wgwb‡U 500 kg cvwb D‡Ëvjb K‡i| hw` 20% ÿgZvi AcPq nq Zvn‡j BwÄbwUi cÖK...Z ÿgZv KZ? [BUET 12-13] mgvavb: Pout = Pin    mgh t = Pin    Pin = mgh t  1  = (500  9.8  200) 60  1 80% W = 20416.67 W (Ans.) 8| 1200 kg f‡ii GKwU Mvoxi Bwćbi ÿgZv 134.05 H.P I Kg©`ÿZv 90%| MvwowU‡K w ̄’ive ̄’v †_‡K 30 ms–1 †e‡M Avb‡Z b~ ̈bZg KZ mgq jvM‡e? (1 H.P = 0.746 kW) [BUET 10-11]