Bala ukukhawulezisa

Umxholo

• Ifomula yokubala ukukhawulezisa
• Ukukhawulezisa ngokunxulumene nokunyanzela
• Ukukhawulezisa ukubala kwemizekelo

Kwifiziksi, ukukhawulezisa Ligama elinikwe ubukhulu be vector (inesalathiso) esibonisa umahluko kwisantya somzimba ohambayo njengoko ixesha lihamba. Ihlala imelwe ngoonobumba a kunye neyunithi yokulinganisa, kwiNkqubo yaMazwe ngaMazwe ziimitha ngomzuzwana ophindwe kabini (m / s²).

Imvelaphi yale nto ivela kumatshini waseNewtonian, othunyelweyo ukuqinisekisa ukuba into iya kuhlala ihamba ngendlela ye-rectilinear ngaphandle kokuba imikhosi ekhokelela ekukhawuleziseni impinge kuyo, ekhokelela kwindlela egobile.

Oku kuthetha ukuba into ekuhambeni kwe-rectilinear inokutshintsha kuphela isantya sayo ukuba inyanzelo lisebenza kuyo elibangela ukukhawulezisa: kwicala elifanayo lendlela yokuhamba kwayo (ukukhawulezisa: izuza isantya) okanye kwicala elichaseneyo (ukuncipha: ilahla isantya) .

Ifomula yokubala ukukhawulezisa

Ke, oomatshini abaphambili bachaza ukukhawulezisa njengokwahluka kwesantya ekuhambeni kwexesha kwaye bacebisa le fomyula ilandelayo:

= dV / dt

Phi ukuya kukukhawulezisa, dV Umahluko kwisantya kunye dt ixesha apho ukukhawulezisa kwenzeka. Zombini ezi zinto zixabisekileyo zichazwe ngolu hlobo lulandelayo:

I-dV = V_F - V_i

Phi V_F iya kuba sisantya sokugqibela kwaye V_i isantya sokuqala seselfowuni. Kubalulekile ukugcina lo myalelo ukubonisa umkhombandlela wokukhawulezisa: kunokubakho ukukhawulezisa okuhle (ukufumana isantya) okanye ukungalunganga (ukulahla isantya). Kwaye:

dt = tf-ti

Phi t_F iya kuba lixesha lesiphelo kwaye t_i ixesha lokuqala lokuhamba. Ngaphandle kokuba kuchazwe ngenye indlela, ixesha lokuqala liya kuhlala liyimizuzwana eyi-0.

Ukukhawulezisa ngokunxulumene nokunyanzela

Kwelinye icala, oomatshini baseNewtonian bamisela umzimba wobunzima obungapheliyo (m), oboniswe ngumbonisi ongaphakathi, ubudlelwane obulinganayo ngokubhekisele kumandla asetyenziswa kwinto leyo (F) kunye nokukhawulezisa okufunyenweyo (a), Oko kukuthi:

F = m. ukuya

Obu budlelwane busebenza kuyo nayiphi na inkqubo yesalathiso kwaye buvumela ukukhawulezisa ukubalwa ngale ndlela ilandelayo:

a = F / m

Olu qulunqo lulandela umthetho wesibini kaNewton (uMthetho osisiseko weDynamics).

Ukukhawulezisa ukubala kwemizekelo

1. Imoto ebalekayo inyusa isantya sayo kumanqanaba angama-18.5 m / s ukuya kuma-46.1 m / s kwimizuzwana eyi-2.47. Kuya kuba yintoni ukukhawulezisa kwayo okuphakathi?

i = dv / dt = (v_F - v_i/ / t_F - t_iApho v_F = 46.1 m / s, v_i = 18.5 m / s, t_F = 2.47 s, t_i = 0 iiseti.

Ke: a = (46.1 - 18.5) / 2.47 = 11.17 m / s²

1. Umqhubi wesithuthuthu uhamba nge-22.4 m / s kwaye aqonde ukuba wenze indlela engeyiyo. Ukubetha iziqhoboshi kwaye isithuthuthu siyeke kwimizuzwana emi-2.55. Yintoni eya kuba kukunciphisa?

i = dv / dt = (v_F - v_i/ / t_F - t_i), apho uV_F = 0 m / s, v_i = 22.4 m / s, t_F = 2.55 s, t_i = 0 iiseti.

Ke:a = (0 - 22.4) / 2.55 = -8.78 m / s²

1. Amandla obunzima beewton ezili-10 asebenza ngokufanayo kubunzima beekhilogram ezi-2. Kuya kuba yintoni ukukhawulezisa kwento etyaliweyo?

a = F / m, apho F = 10 N, m = 2Kg.

Ke ngoko:

a = 10/2 = 5 m / s²

1. Umntu othile utsala ifanitshala ye-400-kg kwelinye icala ngamandla e-net yeetoni ezili-150. Omnye umntu uyityhalela kwicala elinye ngamandla angama-newton angama-200, kodwa kukho umoya ovuthuza kwicala elingaphaya ngamandla ee-newton ezili-10. Kuya kuba yintoni ukukhawulezisa okufumana ifanitshala?

Siyazi ukuba a = F / m, apho amandla omnatha aya kuba sisixa salabo bakwicala elinye kususwe lowo ubaphikisayo: F = 150 N (umntu 1) + 200 N (umntu 2) - 10N (umoya) Iziphumo ezingama 340 N. Siyazi kananjalo ukuba m = 400 kg.

Kamva:a = 340 N / 400 kg = 0.85 m / s²

1. Inqwelo-moya elawulwa kude, enobunzima obuyi-10 kg, ihamba nge-2 m / s² usinga emantla. Kanye ngelo xesha kuvuthuza umoya ngasempuma, ngamandla e-100 N. Yintoni eya kuba kukukhawulezisa okutsha kwenqwelomoya egcina indlela yayo?

Kuba amandla omoya ajonge ngqo kulwalathiso lwenqwelomoya, ayizukuchaphazela ukushukuma kwayo. Iya kuqhubeka ukukhawulezisa emantla nge-2 m / s².

1. Abantwana ababini, omnye ubuthathaka kwaye omnye womelele, badlala umlo wemfazwe, ngamnye kwelinye icala lentambo. Eyokuqala itsala ngasekhohlo ngamandla e-5 N kwaye eyesibini itsala kwicala eliphambeneyo ngamandla e-7 N. Ukuthathela ingqalelo ukuba i-newton (1) ilingana ne-1 kilogram-meter / yesibini iphindwe kabini (kg-m / s2), siyintoni isantya sokufikelela komzimba womntwana obuthathaka, xa utsalwa kwelinye icala?

Ukusuka ku-F = m siyazi ukuba a = F / m, kodwa kufuneka sifumane amandla omnatha, aya kuba ngu-2 N (7 N kwinkwenkwe eyomeleleyo- 5 N kwinkwenkwe engenamandla).

Emva koko, kufuneka sifumane ubunzima, obenzelwe ukubalwa kufuneka buhlukaniswe namandla alwa nomntwana obuthathaka, angala: 1 N = 1kg.m / s²Oko kukuthi, sisixa samandla sokuhlanganisa ikhilogram enye yobunzima kwimitha enye ngomzuzwana ophindwe kabini.

Ke ngoko, ukusuka kwi-5N = 5kg.m / s². Ngenxa yoko, m = 5Kg.

Kwaye ekugqibeleni, siyazi ukuba a = 2N (F) / 5kg (m) = 0.4 m / s²

1. Ilori yomlilo inyusa isantya sayo ukusuka kwi-0 iye kwi-21m / s ukuya eMpuma, kwimizuzwana emi-3.5. Yintoni ukukhawulezisa kwayo?

Siyazi ukuba: V_i = 0 m / s, V_F= 21 m / s, t = 3.5 imizuzwana. Ke ngoko sisebenzisa ifomula:

i = dv / dt = (v_F - v_i/ / t_F - t_i), Oko kukuthi, a = 21m / s / 3.5 s = 6 m / s²

1. Imoto icotha ukusuka kwi-21m / s ukuya kwi-7m / s eMpuma kwimizuzwana eyi-3.5.0. Yintoni ukukhawulezisa kwayo?

Ukwazi ukuba u-V_i = 21 m / s, V_F= 7 m / s, t = 3.5 imizuzwana, kwaye a = dv / dt = (v_F - v_i/ / t_F - t_i), kulula ukuyibala:

a = 7m / s - 21m / s / 3.5s = -4m / s²Oko kukuthi, ukukhawulezisa okungalunganga (ukuncipha).