Question

Um automóvel que se desloca com uma velocidade constante de 90 km/h quer ultrapassar outro que se desloca com uma velocidade constante de 72 km/h, numa mesma estrada reta. O primeiro encontra-se 300 m atrás no instante t = 0. Em quanto tempo o primeiro realizará seu intento?

Answer 1

Primeiro vamos converter Km/h para m/s:

* 72Km/h = 72m/3,6s = 20m/s
* 54Km/h = 54m/3,6s = 15m/s

*** Depois vamos escrever a equação horária de ambos os móveis, seguindo a fórmula: S = So + V.t

Onde:
S = posição final
So = posição inicial
V = velocidade
t = tempo

*** As equações horárias de ambos os móveis são:

S1 = 20t

S2 = 200 + 15t

*** Quando ambos estiverem lado a lado, as posições de ambos serão iguais, ou seja, S1 = S2. Então, basta igualar as duas equações e encontrar o tempo t.

S1 = S2
20t = 200 + 15t
20t -15t = 200
5t = 200
t = 200 / 5
t = 40s

*** Resposta: no instante 40s


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GMTDetect languageAfrikaansAlbanianArabicArmenianAzerbaijaniBasqueBelarusianBengaliBosnianBulgarianCatalanCebuanoChichewaChinese (Simplified)Chinese (Traditional)CroatianCzechDanishDutchEnglishEsperantoEstonianFilipinoFinnishFrenchGalicianGeorgianGermanGreekGujaratiHaitian CreoleHausaHebrewHindiHmongHungarianIcelandicIgboIndonesianIrishItalianJapaneseJavaneseKannadaKazakhKhmerKoreanLaoLatinLatvianLithuanianMacedonianMalagasyMalayMalayalamMalteseMaoriMarathiMongolianMyanmar (Burmese)NepaliNorwegianPersianPolishPortuguesePunjabiRomanianRussianSerbianSesothoSinhalaSlovakSlovenianSomaliSpanishSundaneseSwahiliSwedishTajikTamilTeluguThaiTurkishUkrainianUrduUzbekVietnameseWelshYiddishYorubaZuluAfrikaansAlbanianArabicArmenianAzerbaijaniBasqueBelarusianBengaliBosnianBulgarianCatalanCebuanoChichewaChinese (Simplified)Chinese (Traditional)CroatianCzechDanishDutchEnglishEsperantoEstonianFilipinoFinnishFrenchGalicianGeorgianGermanGreekGujaratiHaitian CreoleHausaHebrewHindiHmongHungarianIcelandicIgboIndonesianIrishItalianJapaneseJavaneseKannadaKazakhKhmerKoreanLaoLatinLatvianLithuanianMacedonianMalagasyMalayMalayalamMalteseMaoriMarathiMongolianMyanmar (Burmese)NepaliNorwegianPersianPolishPortuguesePunjabiRomanianRussianSerbianSesothoSinhalaSlovakSlovenianSomaliSpanishSundaneseSwahiliSwedishTajikTamilTeluguThaiTurkishUkrainianUrduUzbekVietnameseWelshYiddishYorubaZuluText-to-speech function is limited to 200 charactersOptions : History : Feedback : DonateClose