Tsarin Aiki da Ka'idar Makamashin Aiki-Kinetic

Misalan tambayoyi da dabarun aiki da ka'idar makamashin aiki-kinetic

Ƙoƙari

1. Wani jika yana tura keken guragu na kakarsa a cikin wani wurin shakatawa mai da'ira da ƙarfin N20, radius na wurin shakatawa shine mita 7, nawa ne aikin jikan yake yi na juyawa sau biyu?

1. 0 joules
2. 1400 joules
3. 1540 joules
4. 1760 joules

Tattaunawa
Tsarin Kasuwanci: Aiki = Ƙarfi x Matsarwa
Idan jikan ya tura keken guragu sau biyu, jikan da keken guragu za su koma matsayinsu na asali. Tunda komawarsu zuwa matsayinsu na asali sifili ne, wurin da aka mayar da shi sifili ne.
Don haka ƙoƙarin da jikan ya yi ba shi da sifili.
Amsar da ta dace ita ce A.

2. Mai shara yana tura kabad a ƙasa da ƙarfin N350. Ƙasa tana da ƙarfin gogayya na N70. Aikin da aka yi don motsa kabad ɗin mita 6 shine:

1. 45 J
2. 72 J
3. 1680 J
4. 2580 J

Tattaunawa
An san cewa:
Ƙarfin turawa (F) = 350 Newton
Ƙarfin gogayya (F)_shafa) = 70 Newton
Canja wurin kabad (s) = mita 6
An tambaya: Kasuwanci (W)
Amsa:
Akwai ƙarfi biyu da ke aiki a kan wani abu, wato ƙarfin turawa (F) da ƙarfin gogayya (F)._shafa).
Ƙarfin turawa yana daidai da yadda kabad ɗin ke motsawa, don haka ƙarfin turawa yana aiki mai kyau. Akasin haka, ƙarfin jayayya yana akasin yadda kabad ɗin ke motsawa, don haka ƙarfin jayayya yana aiki mara kyau.
Aikin da ƙarfin turawa ke yi:
W = Fs = (Newton 350)(mita 6) = 2100 Mita Newton = Joules 2100
Ana aiwatar da aikin ta hanyar ƙarfin gogayya:
W = – (F_shafa)(s) = – (Newton 70)(mita 6) = – 420 Mita Newton = – Joules 420
Jimlar ƙoƙari:
Jimlar W = Joules 2100 – Joules 420
Jimlar W = Joule 1680
Amsar da ta dace ita ce C.

Ka'idar makamashin aiki-kinetic

3. Ƙarfin da ke ci gaba da aiki na 8 N yana aiki akan abu mai nauyin kilogiram 16. Idan abu yana hutawa da farko, to saurin abu bayan ƙarfin yana aiki na daƙiƙa 4 shine….

1. 0,5 m / s
2. 2 m / s
3. 4 m / s
4. 8 m / s

Tattaunawa
An san cewa:
Ƙarfin da ke tsaye (F) = 8 Newton
Nauyin abu (m) = 16 kg
Saurin farko na abu (v)_o) = 0 m/s
Tazarar lokacin da ƙarfin ke aiki akan abu (t) = daƙiƙa 4
An tambaya: Saurin ƙarshe na abu (v)_t)
Amsa:
Aiki = Canjin kuzarin motsi
W = EK na ƙarshe - EK na farko
W = ½ mv_t² – ½ mv_o²
W = ½ mv_t² - 0
W = ½ mv_t² —— Daidaito ta 1

Aiki = Ƙarfi x Matsarwa
W = Fs
W = s 8
Yi amfani da dabarar GLBB don ƙididdige canjin (s)
s = v_o t + ½ a²
Bayani: s = ƙaura, v_o = saurin farko, t = lokaci, a = hanzari
s = 0 + ½ a² = ½ a² —-> a = (v_t - v_o) / t = v_t
s = ½ (v_t / t) t²
s = ½ (v_t) t
Maye gurbin (s) na matsugunin aiki da matsugunin (s) a cikin wannan lissafin:
W = s 8
W = 8(1/2)(v_t)(t)
W = (4)(v_t)(t) —— Daidaito na 2

Daidaito 1 = Daidaito 2
W = W
½ mv_t² = (4)(v_t)(t)
½ mv_t = (4)(t)
½ (16)(v)_t) = 4(4)
8 v_t = 16
v_t = 16/8
v_t = mita 2/daƙiƙa
Amsar da ta dace ita ce B.

4. Don ƙara saurin abu zuwa ninki biyu na saurinsa na asali, ƙoƙarin...

1. Sau 4 ƙarfin motsa jiki na farko
2. Sau 3 ƙarfin motsa jiki na farko
3. Sau 2 ƙarfin motsa jiki na farko
4. Sau 1 ƙarfin motsa jiki na farko

Tattaunawa
An san cewa:
A ce nauyin abin (m) = 1 kg
A ce saurin farko (v)_o) = 1 m/s
Saurin ƙarshe (v)_t) = 2 x saurin farko = 2 x 1 = 2 m/s
An tambaya: Ƙoƙari = …?
Amsa:
Makamashin motsi na farko:
Farkon EK = ½ mv_o² = ½ (1)(1)² = ½ (1)(1) = ½ (1) = 0,5
Ƙarfin motsi na ƙarshe idan saurin abu ya ninka saurinsa na asali sau biyu:
Ƙarshen EK = ½ mv_t² = ½ (1)(2)² = ½ (4) = 2

Ka'idar makamashin aiki-kinetic:
Aiki = Canjin kuzarin motsi
Aiki = Ƙarfin motsi na ƙarshe - Ƙarfin motsi na farko
Ƙoƙari = 2 – 0,5
Ƙoƙari = 1,5

Ƙarfin motsi na farko = 0,5
Ƙoƙari = 3 x 0,5 = 1,5
Don haka don ƙara saurin abu zuwa sau biyu saurinsa na asali yana buƙatar aiki mai yawa. Sau 3 ƙarfin motsa jiki na farko.
Amsar da ta dace ita ce B.

Tushen tambaya:

Tambayoyin OSN na Makarantar Sakandare ta Junior Physics