{"id":158,"date":"2014-11-21T18:17:55","date_gmt":"2014-11-21T18:17:55","guid":{"rendered":"http:\/\/fisicaevestibular.com.br\/novo\/?page_id=158"},"modified":"2024-08-23T12:50:01","modified_gmt":"2024-08-23T12:50:01","slug":"resolucao-dos-exercicios-velocidade-escalar-media-e-ultrapassagens","status":"publish","type":"page","link":"https:\/\/fisicaevestibular.com.br\/novo\/mecanica\/cinematica\/resolucao-dos-exercicios-velocidade-escalar-media-e-ultrapassagens\/","title":{"rendered":"Velocidade escalar m\u00e9dia e ultrapassagens &#8211; Resolu\u00e7\u00e3o"},"content":{"rendered":"<h3 style=\"text-align: center;\"><span style=\"font-size: large;\">Velocidade escalar m\u00e9dia e ultrapassagens<\/span><\/h3>\n<p class=\"MsoNormal\" style=\"text-align: center;\" align=\"center\"><span style=\"color: #000080; font-size: large;\"><span style=\"font-weight: bold;\">Resolu\u00e7\u00f5es<\/span><\/span><\/p>\n<p class=\"MsoNormal\">01- V<sub>m<\/sub>=\u0394S\/ \u0394t=(S<sub>B<\/sub> \u2013 S<sub>A<\/sub>)\/(t<sub>B <\/sub>\u2013 t<sub>A<\/sub>)=70 \u2013 (-40)\/6,0 \u2013 1,0 &#8212; <b>V<sub>m<\/sub>=22m\/s<\/b><\/p>\n<p class=\"MsoNormal\">02- Primeiro trecho &#8212; Vm1=\u0394S1\/\u03941 &#8212; 54= \u0394S1\/1 &#8212; \u0394S1=54km &#8212; tempo de parada \u2013 \u0394p=0,5h &#8212; segundo trecho &#8212; Vm2=\u0394S2\/\u0394t2 &#8212; 36= \u0394S2\/0,5 &#8212; \u0394S2=18km &#8212; VmT=\u0394St\/\u0394tT=(54 + 18)\/(1 + 0,5 + 0,5) &#8212; VmT=36km\/h\/3,6=10m\/s &#8212; R- A<\/p>\n<p class=\"MsoNormal\">03- Vm=\u0394S\/\u0394t &#8212; 4=1.000\/\u0394t &#8212; \u0394t=1.000\/4=250\/24=10,4 dias &#8212; R- B<\/p>\n<p class=\"MsoNormal\">04- Aplicando Pit\u00e1goras &#8212; \u0394S<sup>2<\/sup>= 8<sup>2<\/sup>+ 6<sup>2<\/sup> &#8212; \u0394S=10m<\/p>\n<p class=\"MsoNormal\" style=\"text-align: center;\" align=\"center\"><img decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/images\/cinematica2\/image053.jpg\" alt=\"\" width=\"192\" height=\"120\" \/><\/p>\n<p class=\"MsoNormal\">V<sub>m<\/sub>=10\/20 &#8212; <b>V<sub>m<\/sub>=0,5m\/s<\/b><\/p>\n<p class=\"MsoNormal\">05- \u0394S=245 \u2013 200 &#8212; \u0394S=45km &#8212; \u0394t=0,5h &#8212; V<sub>m<\/sub>=45\/0,5 &#8212; V<sub>m<\/sub>=90km\/h &#8212; <b>R- B<\/b><\/p>\n<p class=\"MsoNormal\">06- d<sub>total<\/sub>=d<sub>A<\/sub> + d<sub>B<\/sub> +d<sub>C<\/sub><br \/>\nI &#8212; V<sub>total<\/sub>=(d<sub>A<\/sub> + d<sub>B<\/sub> + d<sub>C<\/sub>)\/(t<sub>A <\/sub>+ t<sub>B<\/sub> + t<sub>C<\/sub>) &#8212; V<sub>total<\/sub>=( d<sub>A<\/sub> + d<sub>B <\/sub>+ d<sub>C<\/sub>)\/(d<sub>A<\/sub>\/V<sub>A<\/sub> + d<sub>B<\/sub>\/V<sub>B<\/sub> + d<sub>C<\/sub>\/V<sub>C<\/sub>)<br \/>\nII &#8212; dividindo I por II &#8212; I\/II= ( d<sub>A<\/sub> + d<sub>B<\/sub> + d<sub>C<\/sub>)\/X(d<sub>A<\/sub>\/V<sub>A <\/sub>+ d<sub>B<\/sub>\/V<sub>B<\/sub> + d<sub>C<\/sub>\/V<sub>C<\/sub>)\/ ( d<sub>A<\/sub> + d<sub>B<\/sub> + d<sub>C<\/sub>) <b>&#8212; R- A<\/b><\/p>\n<p class=\"MsoNormal\">07- Tendo ou n\u00e3o fio, a ida \u00e9 atrav\u00e9s de ondas eletromagn\u00e9ticas e, nesta dist\u00e2ncia, a propaga\u00e7\u00e3o \u00e9 instant\u00e2nea e portanto leva-se em conta apenas a volta do som pelo ar com velocidade de 330ms &#8212; 330=330\/\u0394t &#8212; \u0394t=1s &#8212; <b>R- A<\/b><\/p>\n<p class=\"MsoNormal\">08- a) Deve percorrer 400m na horizontal e 300m na vertical<\/p>\n<p class=\"MsoNormal\" style=\"text-align: center;\" align=\"center\"><img decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/images\/cinematica2\/image054.jpg\" alt=\"\" width=\"144\" height=\"98\" \/><\/p>\n<p class=\"MsoNormal\">\u0394S<sub>m\u00ednima<\/sub>= 400 + 300 &#8212; <b>\u0394S<sub>m\u00ednim<\/sub>=700m<\/b><\/p>\n<p class=\"MsoNormal\">b) O deslocamento do metr\u00f4 vale \u0394S<sup>2<\/sup>=400<sup>2 <\/sup>+ 300<sup>2<\/sup> &#8212; \u0394S=500m &#8212; 36\/3,6=500\/\u0394t &#8212; \u0394t=500\/10 &#8212; <b>T<sub>m<\/sub>=50s<\/b><\/p>\n<p class=\"MsoNormal\">c) carro &#8212; 18\/3,6=700\/T<sub>c<\/sub> &#8212; T<sub>c<\/sub>=140s &#8212; T<sub>c<\/sub>\/T<sub>m<\/sub>=140\/50 &#8212; <b>Tc\/T<sub>m<\/sub>=2,8<\/b><\/p>\n<p class=\"MsoNormal\">09- a) Observe no gr\u00e1fico que as rodas da frente demoram \u0394t=0,1s para pressionar os sensores S(1) e depois S(2), percorrendo \u0394S=2m &#8212; V=2\/0,1 &#8212; <b>V=20m\/s=72km\/h<\/b><\/p>\n<p class=\"MsoNormal\">b) As rodas dianteiras e as traseiras demoram \u0394t=0,15s para passarem por um dos sensores com velocidade de 20m\/s &#8212; 20= \u0394S\/0,15 &#8212; <b>\u0394S=3m<\/b><\/p>\n<p class=\"MsoNormal\">10- 1ano=365diasX24hX3.600s &#8212; 1 ano=31.536.000s &#8212; 10 mil\u00eanios=10X1000X31.536.000=315.360.000.000s &#8212; 10 mil\u00eanios = 3,1536.10<sup>11<\/sup>s &#8212; V=\u0394S\/ \u0394t &#8212; 3.10<sup>8<\/sup>= \u0394S\/ 3,1536.10<sup>11 <\/sup>&#8212; \u0394S=9,4608.10<sup>11<\/sup> &#8212; \u0394S=10.10<sup>11<\/sup>.10<sup>8<\/sup>=10<sup>20<\/sup>m = 10<sup>17<\/sup>km &#8212; <b>R- B<\/b><\/p>\n<p class=\"MsoNormal\">11- 1ano=365diasX24hX3.600s &#8212; 1 ano=31.536.000s &#8212; 10 mil\u00eanios=10X1000X31.536.000=315.360.000.000s &#8212; 10 mil\u00eanios = 3,1536.10<sup>11<\/sup>s<br \/>\n&#8212; V=\u0394S\/ \u0394t &#8212; 3.10<sup>8<\/sup>= \u0394S\/ 3,1536.10<sup>11 <\/sup>&#8212; \u0394S=9,4608.10<sup>11<\/sup> &#8212; \u0394S=10.10<sup>11<\/sup>.10<sup>8<\/sup>=10<sup>20<\/sup>m = 10<sup>17<\/sup>km &#8212; <b>R- B<\/b><\/p>\n<p class=\"MsoNormal\">12- Tempo que ele demora para percorrer o trecho total &#8212; V<sub>mtotal<\/sub>= \u0394S<sub>total<\/sub>\/ \u0394t<sub>total<\/sub> &#8212;<br \/>\n80=40\/ \u0394t<sub>total<\/sub> &#8212; \u0394t<sub>total<\/sub>=0,5h &#8212; nos primeiros 15min, com velocidade m\u00e9dia de 40km\/h, ele percorreu &#8212; V<sub>1<\/sub>=\u0394S<sub>1<\/sub>\/\u0394t<sub>1<\/sub> &#8212; 40= \u0394S<sub>1<\/sub>\/(15\/60) &#8212; \u0394S<sub>1<\/sub>=10km<br \/>\n&#8212; falta percorrer &#8212; \u0394S<sub>2<\/sub>=(40 \u2013 10)=30km em \u0394t<sub>2<\/sub>=(0,5 \u2013 0,25)=0,25h &#8212; V<sub>2<\/sub>=30\/0,25 &#8212; V<sub>2<\/sub>=120km\/h &#8212; <b>R- C<\/b><\/p>\n<p class=\"MsoNormal\">13- 5=\u0394S\/20 &#8212; <b>\u0394s=100m<\/b><\/p>\n<p class=\"MsoNormal\">14- a) 1.540=2.0,1\/\u0394t &#8212; \u0394t=0,0013 &#8212; <b>\u0394t=1,3.10<sup>-3 <\/sup>s<\/b><\/p>\n<p class=\"MsoNormal\">b) 1.540=d\/0,25.10<sup>-4<\/sup>(s\u00f3 volta) &#8212; d=3,85cm &#8212; d\u2019=10 \u2013 3,85 &#8212; <b>d\u2019=6,15cm<\/b><\/p>\n<p class=\"MsoNormal\">15- A resolu\u00e7\u00e3o desse exerc\u00edcio envolve o conceito de velocidade relativa, explicado pelas figuras abaixo:<\/p>\n<p class=\"MsoNormal\" style=\"text-align: center;\" align=\"center\"><img fetchpriority=\"high\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/images\/cinematica2\/image055.jpg\" alt=\"\" width=\"392\" height=\"129\" \/><\/p>\n<p class=\"MsoNormal\">Na figura 1 onde eles se movem no mesmo sentido, a velocidade relativa entre eles (velocidade com que 2 se afasta de 1) vale V<sub>R1<\/sub>=V<sub>2<br \/>\n\u00ad\u00ad<\/sub>&#8211; V<sub>1<\/sub> &#8212; 100\/1=V<sub>2 \u00ad\u00ad<\/sub>&#8211; V<sub>1<\/sub> &#8212; 100=V<sub>2<br \/>\n\u00ad\u00ad<\/sub>&#8211; V<sub>1<\/sub> I &#8212; na figura 2, onde eles se movem em sentidos contr\u00e1rios, a velocidade relativa entre eles (velocidade com que 2 se aproxima de 1) vale &#8212; V<sub>R2<\/sub>=V<sub>2 \u00ad\u00ad<\/sub>+ V<sub>1<\/sub> &#8212; 90\/0,1=V<sub>2<\/sub><br \/>\n+ V<sub>1<\/sub> &#8212; 900=V<sub>2<\/sub> + V<sub>1<\/sub> &#8212;<\/p>\n<p class=\"MsoNormal\">V<sub>2<\/sub>=900 \u2013 V<sub>1<\/sub> II &#8212; substituindo II em I &#8212; 100=(900 \u2013 V<sub>1<\/sub>) \u2013 V<sub>1<\/sub> &#8212; 2V<sub>1<\/sub>=800 &#8212; V<sub>1<\/sub>=400cm\/s=4m\/s &#8212; V<sub>2<\/sub>=900 \u2013 400 &#8212;<\/p>\n<p class=\"MsoNormal\">V<sub>2<\/sub>=500cm\/s=5m\/s &#8212; <b>R- C<\/b><\/p>\n<p class=\"MsoNormal\">16- Ida &#8212; V<sub>i<\/sub>=\u0394S<sub>i<\/sub>\/\u0394t<sub>i <\/sub>&#8212; 70=7\/\u0394t<sub>i<\/sub> &#8212; \u0394t<sub>i<\/sub>=1\/10h &#8212; trecho total &#8212; V<sub>t<\/sub>=\u0394S<sub>t<\/sub>\/\u0394t<sub>t<\/sub> &#8212; V<sub>t<\/sub>= (7 + 6)\/(1\/10 + 1\/3) &#8212;V<sub>t<\/sub>=13\/(3 + 10)\/30 &#8212; V<sub>t<\/sub>=30km\/h &#8212; volta &#8212; V<sub>v<\/sub>=\u0394S<sub>v<\/sub>\/\u0394t<sub>t<\/sub> &#8212; V<sub>v<\/sub>=13\/(1\/6) &#8212; V<sub>v<\/sub>=78km\/h &#8212; <b>R- A<\/b><\/p>\n<p class=\"MsoNormal\">17- Dist\u00e2ncia percorrida por cada um desses instant\u00e2neos &#8212; \u0394S=2.4,2.10<sup>10<\/sup>m &#8212; o intervalo de tempo entre esses 12 instant\u00e2neos foi de 11 idas e voltas &#8212; 11.34min=11X2.040 &#8212; \u0394t=22.440s &#8212; V=\u0394S\/\u0394t &#8212; 35.000=\u0394S\/22.440 &#8212; \u0394S=785.400.000m &#8212; \u0394S=785.400km &#8212; <b>\u0394S=7,9.10<sup>5<\/sup>km<\/b><\/p>\n<p class=\"MsoNormal\">18-<\/p>\n<p class=\"MsoNormal\">1<sup>a<\/sup> metade &#8212; V<sub>1<\/sub>=\u0394S<sub>1<\/sub>\/\u0394t<sub>1 <\/sub>&#8212; 60=d\/ \u0394t<sub>1<\/sub> &#8212; \u0394t<sub>1<\/sub>=d\/60 &#8212;<\/p>\n<p class=\"MsoNormal\">2<sup>a <\/sup>metade &#8212; V<sub>2<\/sub>=\u0394S<sub>2<\/sub>\/\u0394t<sub>2<\/sub> &#8212; 90=d\/ \u0394t<sub>2 <\/sub>&#8212; \u0394t<sub>2<\/sub>=d\/90 &#8212;<\/p>\n<p class=\"MsoNormal\" style=\"text-align: center;\" align=\"center\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/images\/cinematica2\/image056.jpg\" alt=\"\" width=\"442\" height=\"78\" \/><\/p>\n<p class=\"MsoNormal\">V<sub>total<\/sub>=\u0394S<sub>total<\/sub>\/ \u0394t<sub>total <\/sub>&#8212; V<sub>total<\/sub>=2d\/(d\/60 + d\/90)=2d\/(5d\/180) &#8212; V<sub>total<\/sub>=2dX180\/5d<br \/>\n&#8212; <b>V<sub>total<\/sub>=72km\/h<\/b><\/p>\n<p class=\"MsoNormal\">19- Observe que durante todo o percurso de 15km o metr\u00f4 ficou parado durante 5 minutos (1 minuto em cada esta\u00e7\u00e3o com exce\u00e7\u00e3o do Bosque \u201cde onde partiu\u201d e do Terminal \u201conde chegou\u201d) &#8212; de Vila Maria de onde partiu quando t=1 minuto at\u00e9 Felicidade onde chegou quando t=5 minutos ele demorou \u0394t=(5 \u2013 1)=4s e percorreu \u0394S=2km &#8212; V=2\/4 &#8212; V=0,5km\/h (durante todo o prrcurso, pelo enunciado) &#8212; tempo que demora para percorrer o trecho total de 15km com velocidade m\u00e9dia de 0,5km\/h &#8212; 0,5=15\/\u0394t &#8212; \u0394t=30 minutos &#8212; \u0394t<sub>total<\/sub>=30 (tempo de movimento) +<br \/>\n5 (tempo parado) &#8212; \u0394t<sub>total<\/sub>=35 min &#8212; <b>R- D<\/b><\/p>\n<p class=\"MsoNormal\">20- C\u00e1lculo da altura h do n\u00edvel do mar ao sat\u00e9lite &#8212; V= 3.10<sup>8<\/sup>m\/s &#8212; \u0394t=18\/2.10<sup>-4<\/sup> =9.10<sup>-4<\/sup>s (s\u00f3 volta) &#8212; 3.10<sup>8<\/sup>=h\/9.10<sup>-4<\/sup> &#8212;<\/p>\n<p class=\"MsoNormal\" style=\"text-align: center;\" align=\"center\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/images\/cinematica2\/image057.jpg\" alt=\"\" width=\"240\" height=\"111\" \/><\/p>\n<p class=\"MsoNormal\" style=\"text-align: justify;\">h=27.10<sup>4<\/sup>m &#8212; c\u00e1lculo da altura h\u2019 do topo da geleira at\u00e9 o sat\u00e9lite &#8212; 3.10<sup>8<\/sup>=h\u2019\/8,9.10<sup>-4<\/sup> &#8212; h\u2019=26,7.10<sup>4<\/sup> &#8212; altura da geleira &#8212; h<sub>geleira<\/sub>=27.10<sup>4<\/sup>\u201326,7.10<sup>4<\/sup> &#8212; <b>h<sub>geleira<\/sub>=0,3.10<sup>4<\/sup>=3.000m<\/b><\/p>\n<p class=\"MsoNormal\">21- Velocidade da pessoa &#8212; V=1,5.70cm\/1s &#8212; V=105cm\/s &#8212; \u0394S=21m=2.100cm &#8212; 105=2.100\/\u0394t &#8212; \u0394t=20s &#8212; <b>R- C<\/b><\/p>\n<p class=\"MsoNormal\">22- Em 15min=15\/60=1\/4h ele percorre &#8212; 90=d<sub>1<\/sub>\/(1\/4) &#8212; d<sub>1<\/sub>=22,5km(sem chuva) &#8212; 60=d<sub>2<\/sub>(1\/4) &#8212; de<sub>2<\/sub>=15km (com chuva) &#8212; ele deixou de percorrer d<sub>3<\/sub>=22,5 \u2013 15,0=7,5km e esse deslocamento a 90km\/h demora &#8212; 90=7,5\/\u0394t &#8212; \u0394t=(7,5\/90)X60 &#8212; \u0394t=5 min &#8212; <b>R- A<\/b><\/p>\n<p class=\"MsoNormal\">23- Tempo de percep\u00e7\u00e3o no ar &#8212; 340=17\/\u0394t &#8212; \u0394t=0,05s &#8212; esse tempo \u00e9 o mesmo independente do meio &#8212; 1600= \u0394S\/0,05 &#8212; \u0394S=80m &#8212; <b>R- C<\/b><\/p>\n<p class=\"MsoNormal\">24- Cada quarteir\u00e3o tem lado \u2113<sup>2<\/sup>=10.000 &#8212; \u2113=100m &#8212; cada rua tem largura 10m e o comprimento total da prociss\u00e3o \u00e9 de 240m &#8212; dist\u00e2ncia total percorrida &#8212; d=100 + 10 + 240 &#8212; d=350m &#8212; V=d\/\u0394t &#8212; 0,4=350\/ \u0394t &#8212; \u0394t=875\/60 &#8212; \u0394t=14,6min <b>R- E<\/b><\/p>\n<p class=\"MsoNormal\">25- 100= \u0394S<sub>1<\/sub>\/2 &#8212; \u0394S<sub>1<\/sub>=200km &#8212; 80= \u0394S<sub>2<\/sub>\/1,5 &#8212; \u0394S<sub>2<\/sub>=120km &#8212; V<sub>total<\/sub>= \u0394S<sub>total<\/sub>\/ \u0394t<sub>total<\/sub>=(200 + 120)\/(2 + 0,5 + 1,5) &#8212; V<sub>total<\/sub>=80km\/h &#8212; <b>R- A<\/b><\/p>\n<p class=\"MsoNormal\">26- Em todo hex\u00e1gono regular o raio R \u00e9 igual ao lado \u2113 e ele \u00e9 formado por 6 tri\u00e2ngulos eq\u00fcil\u00e1teros, cada um com \u00e2ngulo de 60<sup>o<\/sup> &#8212;<\/p>\n<p class=\"MsoNormal\" style=\"text-align: center;\" align=\"center\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/images\/cinematica2\/image058.jpg\" alt=\"\" width=\"141\" height=\"124\" \/><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/images\/cinematica2\/image059.jpg\" alt=\"\" width=\"158\" height=\"156\" \/><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/images\/cinematica2\/image060.jpg\" alt=\"\" width=\"192\" height=\"125\" \/><\/p>\n<p class=\"MsoNormal\">\u03b1=60<sup>o<\/sup> + 60<sup>o<\/sup> &#8212; \u03b1=120<sup>o<\/sup> &#8212; R=10cm &#8212; TM=30cm &#8212; MF=50cm &#8212; lei dos cossenos &#8212; (FT)<sup>2 <\/sup>=(TM)<sup>2<\/sup> + (MF)<sup>2<\/sup> -2.(TM).(MF).cos120<sup>o<\/sup> &#8212; (FT)<sup>2<\/sup>=900 + 2500 \u2013 2.30.50.(-1\/2) = 4.900 &#8212; FT = 70cm &#8212; V=70\/10 &#8212; V=7cm\/s &#8212; <b>R- D<\/b><\/p>\n<p class=\"MsoNormal\">27- 1<sup>a<\/sup> etapa \u2013 V=(1\/9).d\/\u0394t<sub>1<\/sub> &#8212; \u0394t<sub>1<\/sub>=d\/9V &#8212; 2<sup>a<\/sup> etapa \u2013 2V=(8\/9).d.\u0394t<sub>2<\/sub> &#8212; \u0394t<sub>2<\/sub>=4d\/9V &#8212; trecho total &#8212; V<sub>t<\/sub>=d\/(d\/9V + 4d\/9V) &#8212; V<sub>t<\/sub>=d\/(5d\/9V) &#8212; V<sub>t<\/sub>=d.9V\/5d &#8212; V<sub>t<\/sub>=9V\/5 &#8212; <b>R- A<\/b><\/p>\n<p class=\"MsoNormal\">28-a) Para atravessar um farol a dist\u00e2ncia percorrida por um ponto P fixo em qualquer ponto do trem \u00e9 \u0394S=x=100m &#8212; 20=100\/\u0394t &#8212; <b>\u0394t=5s<\/b><\/p>\n<p class=\"MsoNormal\">b) Observe na figura abaixo que, para atravessar totalmente o t\u00fanel um ponto P fixo em qualquer parte do trem deve percorrer<\/p>\n<p class=\"MsoNormal\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/images\/cinematica2\/image061.jpg\" alt=\"\" width=\"767\" height=\"147\" \/><\/p>\n<p class=\"MsoNormal\">a dist\u00e2ncia \u2013 \u0394S= x(comprimento do trem) + c(comprimento do t\u00fanel \u201cponte\u201d) &#8212; \u0394S= (200 + 100) &#8212; V= \u0394S\/ \u0394t &#8212; 20=(300\/ \u0394t) &#8212; <b>\u0394t=15s<\/b><\/p>\n<p class=\"MsoNormal\">29- Diferen\u00e7a entre as velocidades \u2013 mesmo sentido \u2013 V<sub>R<\/sub>=(V<sub>2 <\/sub>\u2013 V<sub>1<\/sub>)=\u0394S\/\u0394t &#8212; (V<sub>2<\/sub> \u2013 V<sub>1<\/sub>)=(10 + 10)\/4 &#8212; (V<sub>2<\/sub> \u2013 V<sub>1<\/sub>)=5m\/s<\/p>\n<p class=\"MsoNormal\" style=\"text-align: center;\" align=\"center\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/images\/cinematica2\/image062.jpg\" alt=\"\" width=\"575\" height=\"108\" \/><\/p>\n<p class=\"MsoNormal\"><b>R- C<\/b><\/p>\n<p>30- V<sub>R<\/sub>=\u0394S\/\u0394t &#8212; 2V \u2013 V=100\/\u0394t &#8212; \u0394t=100\/V (tempo que ele demora para ultrapassar o vag\u00e3o) &#8212; V<sub>homem<\/sub>=2V=\u0394S<sub><span style=\"font-size: 12.0pt;\">homem<\/span><\/sub><span style=\"font-size: 12.0pt;\">\/<\/span>\u0394t &#8212;<\/p>\n<p class=\"MsoNormal\" style=\"text-align: center;\" align=\"center\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/images\/cinematica2\/image063.jpg\" alt=\"\" width=\"289\" height=\"130\" \/><\/p>\n<p class=\"MsoNormal\">2V= \u0394S<sub><span style=\"font-size: 12.0pt;\">homem<\/span><\/sub><span style=\"font-size: 12.0pt;\">\/(100\/V) &#8212; <\/span>\u0394S<sub><span style=\"font-size: 12.0pt;\">homem<\/span><\/sub><span style=\"font-size: 12.0pt;\">=200V\/V &#8212; <\/span><b>\u0394S<sub><span style=\"font-size: 12.0pt;\">homem<\/span><\/sub><span style=\"font-size: 12.0pt;\">=200m<\/span><\/b><\/p>\n<p class=\"MsoNormal\">31- Sentidos opostos &#8212; V<sub>R<\/sub>=18 + 27=45km\/h\/3,6=12,5 &#8212; V<sub>R<\/sub>=12,5m\/s &#8212; 12,5= \u0394S\/ \u0394t &#8212; 12,5=(200 + 250)\/ \u0394t &#8212; <b>\u0394t=36s<\/b> &#8212; <b>R- C<\/b><\/p>\n<p>32- 50\/3,6=(120 + d)\/15 &#8212; 750=3,6d + 432 &#8212; d=318\/3,6 &#8212; d=88,33m &#8212; <b>R- B<\/b><\/p>\n<p class=\"MsoNormal\">33- V<sub>R<\/sub>=(20 \u2013 15)=100\/\u0394t &#8212; \u0394t=20s &#8212; <b>R- C<\/b><\/p>\n<p>34- Sentidos opostos &#8212; V<sub>R<\/sub>=2V + V=3V &#8212; parando o trem menor e consequentemente a pessoa, o trem maior de velocidade relativa 3V e comprimento 90m demora 2s na ultrapassagem &#8212; 3V=90\/2 &#8212; V=15m\/s (velocidade do trem maior) &#8212; como o trem menor tem o dobro da velocidade &#8212; <b>V\u2019=30m\/s<\/b><\/p>\n<p class=\"MsoNormal\">35-<b> <\/b>V<sub>R<\/sub>=V<sub>n\u00ad<\/sub> \u2013 2=50\/20 &#8212; V<sub>n<\/sub>=2 + 2,5 &#8212; V<sub>n<\/sub>=4,5m\/s &#8212; <b>R- D<\/b><\/p>\n<p class=\"MsoNormal\"><b>36- <\/b>Como os caminh\u00f5es deslocam-se em sentidos opostos, o m\u00f3dulo da velocidade relativa entre eles \u00e9 a soma de suas velocidades &#8212; v<sub>r<\/sub> = 50 + 40 = 90 km\/h = 25 m\/s &#8212; essa \u00e9 a velocidade com que o caroneiro v\u00ea o segundo caminh\u00e3o passar por ele &#8212; comprimento desse caminh\u00e3o &#8212; L = v<sub>r<\/sub>.\u0394t = 25.(1) &#8212; L = 25 m &#8212; <b>R- A<\/b><\/p>\n<p class=\"MsoNormal\"><b>37- <\/b>Comprimento de cada volta &#8212; L = 27 km &#8212; c = 3.10<sup>5<\/sup> km\/s &#8212; n = 11.10<sup>3<\/sup> voltas &#8212; \u0394t = 1 s:<\/p>\n<p class=\"MsoNormal\">a) V=\u0394S\/\u0394t &#8212; V=nL\/\u0394t=11.000&#215;27\/1 &#8212; <b>V=2,97.10<sup>5<\/sup>km\/s<\/b><\/p>\n<p class=\"MsoNormal\">b) A raz\u00e3o percentual dessa velocidade em rela\u00e7\u00e3o \u00e0 velocidade da luz \u00e9:<\/p>\n<p class=\"MsoNormal\">r<sub>p<\/sub> =V\/cx100=2,97.10<sup>5<\/sup>\/3.10<sup>5<\/sup>x100 &#8212;<b> r<sub>p<\/sub>=99%<\/b><\/p>\n<p class=\"MsoNormal\">c) A corrida em busca de novas armas envolve tecnologias nucleares. Assim, um primeiro interesse das na\u00e7\u00f5es envolvidas \u00e9 b\u00e9lico. Al\u00e9m disso, a descoberta de novas tecnologias tamb\u00e9m pode ser aproveitada no desenvolvimento de novos produtos, ou mesmo na redu\u00e7\u00e3o dos custos de produ\u00e7\u00e3o, melhorando o poder aquisitivo e a qualidade de vida das pessoas. H\u00e1 ainda um outro interesse que \u00e9 a busca por novas fontes para produ\u00e7\u00e3o de energia.<\/p>\n<p class=\"MsoNormal\"><b>38- <\/b>I. Errada &#8212; 1 ano-luz \u00e9 a dist\u00e2ncia que a luz percorre em 1 ano, no v\u00e1cuo, com velocidade c=3.10<sup>8<\/sup>m\/s=3.10<sup>5<\/sup>km\/s &#8212; d = v t &#8212; d = (3.10<sup>5<\/sup> km\/s)x(2,5.10<sup>6<\/sup> anosx3.10<sup>7 <\/sup>s\/ano) &#8212; d=2,25.10<sup>19<\/sup> km.<\/p>\n<p class=\"MsoNormal\">II. Correta &#8212; veja os c\u00e1lculos efetuados no item anterior.<\/p>\n<p class=\"MsoNormal\">III. Correta.<\/p>\n<p class=\"MsoNormal\"><b>R- E<\/b><\/p>\n<p class=\"MsoNormal\"><b>39- <\/b>V=\u0394S\/\u0394t &#8212; 5=2\/\u0394t &#8212; \u0394t=2\/5=0,4h &#8212; \u0394t=0,4&#215;60=24min &#8212; <b>R- C<\/b><\/p>\n<p class=\"MsoNormal\" style=\"text-align: justify; line-height: 15.65pt;\"><b>40 &#8211; <\/b>Observe pela equa\u00e7\u00e3o da posi\u00e7\u00e3o da formiga em fun\u00e7\u00e3o do tempo S<sub>f<\/sub>=2 + 5t + 4t<sup>2<\/sup> que a posi\u00e7\u00e3o inicial da formiga \u00e9 S<sub>o<\/sub>=2mm e ela se desloca no sentido das posi\u00e7\u00f5es crescentes do eixo (V<sub>of<\/sub>=5mm\/s, positiva) &#8212; como a lesma est\u00e1 a 16mm da formiga e se move no mesmo sentido que ela, a lesma s\u00f3 pode estar na posi\u00e7\u00e3o inicial S<sub>ol<\/sub>=18mm &#8212; a condi\u00e7\u00e3o para que isso ocorra est\u00e1 esquematizada na figura &#8212; a lesma, que tem velocidade constante de V<sub>l<\/sub>=5mm\/s est\u00e1 em movimento uniforme e sua equa\u00e7\u00e3o<\/p>\n<p class=\"MsoNormal\" style=\"text-align: justify; line-height: 15.65pt;\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/images\/Atualizacao\/atualizacao19\/image022.jpg\" alt=\"\" width=\"384\" height=\"100\" \/><\/p>\n<p class=\"MsoNormal\" style=\"text-align: justify; line-height: 15.65pt;\">da posi\u00e7\u00e3o em fun\u00e7\u00e3o do tempo \u00e9 S<sub>l<\/sub> = S<sub>ol<\/sub> + V<sub>oL<\/sub>.t &#8212; S<sub>l<\/sub>=18 + 5t &#8212; no encontro elas ocupam a mesma posi\u00e7\u00e3o, ou seja, S<sub>f<\/sub> = S<sub>l <\/sub><span lang=\"EN-US\">2 + 5t + 4t<sup>2<\/sup> = 18 + 5t &#8212; 4t<sup>2<\/sup> = 16 &#8212; t=2 s &#8212; <b> R- B<\/b><\/span><\/p>\n<p class=\"MsoNormal\"><b><span lang=\"EN-US\">41-<\/span><\/b> No primeiro trecho a dist\u00e2ncia percorrida foi de 75% de 800m &#8212; \u2206S1=0,75&#215;800=600m &#8212; essa dist\u00e2ncia \u2206S1=600m foi perorrida no intervalo de tempo de \u2206t1=(1,717 \u2013 0,417)=78s &#8212; a velocidade m\u00e9dia pedida \u00e9 a do primeiro trecho &#8212; Vm1=\u2206S1\/\u2206t1=600\/78=7,7m\/s<\/p>\n<p class=\"MsoNormal\">R- B<\/p>\n<p class=\"MsoNormal\"><b>42-<\/b> Considere TSE um tri\u00e2ngulo em cujos v\u00e9rtices est\u00e3o localizados, respectivamente, T\u00f3quio, Sendai e o Epicentro &#8212; a<\/p>\n<p class=\"MsoNormal\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/images\/Atualizacao\/atualizacao19\/image028.jpg\" alt=\"\" width=\"163\" height=\"203\" \/><\/p>\n<p class=\"MsoNormal\">dist\u00e2ncia SE pode ser calculada utilizando-se o teorema dos cossenos<\/p>\n<p class=\"MsoNormal\">&#8212; SE2 = TS2 + TE2 \u2013 2.TS.TE.cos\u03b1=3202 + 3602 \u2013 2.320.360.0,934<\/p>\n<p class=\"MsoNormal\">&#8212; ES2 = 102 400 + 129 600 \u2013 2.(25.10).(22.32.10).93,4\/100<\/p>\n<p class=\"MsoNormal\">&#8212; ES2 = 16 900<\/p>\n<p class=\"MsoNormal\">&#8212; ES = 130 km<\/p>\n<p class=\"MsoNormal\">&#8212; Vm=ES\/\u2206t=130\/(13\/60)<\/p>\n<p class=\"MsoNormal\">&#8212; Vm=600 km\/h<\/p>\n<p class=\"MsoNormal\">&#8212; R- E<\/p>\n<p class=\"MsoNormal\" style=\"text-align: justify; line-height: 15.65pt;\"><b>43-<\/b> Ciclones &#8212; vento circular forte, produzida por grandes massas de ar em alta velocidade de rota\u00e7\u00e3o &#8212; os furac\u00f5es s\u00e3o os ciclones que surgem no mar do Caribe (oceano Atl\u00e2ntico) ou nos EUA &#8212; os ventos circulares gerados em torno dos ciclones precisam ter mais de 119 km\/h para uma tempestade ser considerada um furac\u00e3o, como foi o caso do Katrina &#8212; dados &#8212; velocidade de transla\u00e7\u00e3o do Katrina &#8212; V=24km\/h &#8212; dist\u00e2ncia a ser percorrida &#8212; \u2206S=1 200km &#8212; V=\u2206S\/\u2206t &#8212; 24=1 200\/\u2206t &#8212; \u2206t=1 200\/24=50h &#8212; <b> R- E<\/b><\/p>\n<h3 class=\"MsoNormal\" style=\"text-align: justify; line-height: 15.65pt;\"><span style=\"color: #000080;\"><a style=\"color: #000080;\" title=\"Exerc\u00edcios \u2013 Velocidade escalar m\u00e9dia e ultrapassagens\" href=\"http:\/\/fisicaevestibular.com.br\/novo\/mecanica\/cinematica\/velocidade-escalar-media-e-ultrapassagens\/exercicios-velocidade-escalar-media-e-ultrapassagens\/\">Voltar para os Exerc\u00edcios<\/a><\/span><\/h3>\n","protected":false},"excerpt":{"rendered":"<p>Velocidade escalar m\u00e9dia e ultrapassagens Resolu\u00e7\u00f5es 01- Vm=\u0394S\/ \u0394t=(SB \u2013 SA)\/(tB \u2013 tA)=70 \u2013 (-40)\/6,0 \u2013 1,0 &#8212; Vm=22m\/s 02- Primeiro trecho &#8212; Vm1=\u0394S1\/\u03941 &#8212; 54= \u0394S1\/1 &#8212; \u0394S1=54km &#8212; tempo de parada \u2013 \u0394p=0,5h &#8212; segundo trecho &#8212; Vm2=\u0394S2\/\u0394t2 &#8212; 36= \u0394S2\/0,5 &#8212; \u0394S2=18km &#8212; VmT=\u0394St\/\u0394tT=(54 + 18)\/(1 + 0,5 + 0,5) &#8212; VmT=36km\/h\/3,6=10m\/s &#8212; R- A 03- Vm=\u0394S\/\u0394t<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":139,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"class_list":["post-158","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/158","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/comments?post=158"}],"version-history":[{"count":3,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/158\/revisions"}],"predecessor-version":[{"id":10809,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/158\/revisions\/10809"}],"up":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/139"}],"wp:attachment":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/media?parent=158"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}