Questões - AFA 2018 | Gabarito e resoluções

(AFA - 2018) Um corpo M de dimenses desprezveis e massa 10 kg movimentando-se emuma dimenso, inicialmente com velocidade V,vai sucessivamente colidindo inelasticamente com N partculas m, todas de mesma massa 1 kg, e com velocidades de mdulo v = 20 m/s, que tambm se movimentam em uma dimenso de acordo com a Figura 1, a seguir. O grfico que representa a velocidade final do conjunto vfaps cada coliso em funo do nmero de partculas N apresentado na Figura 2, a seguir. Desconsiderando as foras de atrito e a resistncia do ar sobre o corpo e as partculas, a coliso de ordem N0na qual a velocidade do corpo resultante (corpo M + N0 partculas m) se anula, ,

(AFA - 2018) PROVA DE REDAO Com base nos textos abaixo e nos textos da prova de Lngua Portuguesa, bem como no seu conhecimento de mundo, escreva um texto dissertativo-argumentativo, em prosa, sobre a seguinte questo: Os efeitos negativos do uso indiscriminado da internet TEXTO I A partilha de informaes ganhou propores nunca imaginadas com a popularizao das redes sociais. Ganhamos agilidade na troca de informaes e estamos mais prximos. Mas a troca indiscriminada de informaes descontextualizadas e humor porttil deixa uma questo em aberto: estamos perdendo o senso crtico? (http://obviousmag.org/archives/2011/09/redes_sociais_e_colaboracao_extrema_O_fim_do_senso_critico-.html.Fragmento.Acesso em: 21 fev 2017) TEXTO II (SALIMENA, Raphael.In:jottaclub.com/2017/02/comisao-de-educasao-do-senado-imajina-qe-seja-a-ora-de-mudar-portugues-emnova-reforma-ortografica/.Acesso em: 11 mar 2017) Observao: D um ttulo redao. Orientaes a) Considere os textos desta prova como motivadores e fonte de dados. No os copie, sob pena de ter a redao zerada. b) A redao dever conter no mnimo 100 (cem) palavras, considerando-se palavras todas aquelas pertencentes s classes gramaticais da Lngua Portuguesa. c) Recomenda-se que a redao seja escrita em letra cursiva legvel. Caso seja utilizada letra de forma (caixa alta), as letras maisculas devero receber o devido realce. d) Utilize caneta de tinta preta ou azul.

(AFA - 2018) RAIOS CAUSAM 130 MORTES POR ANO NO BRASIL; SAIBA COMO PREVENIR Comeou a temporada de raios e o Brasil o lugar onde eles mais caem no mundo. Os raios so fenmenos da natureza impressionantes, mas causam mortes e prejuzos. Todos os anos morrem em mdia 130 pessoas no pas atingidas por essas descargas eltricas. (...) (...) Segundo as pesquisas feitas pelo grupo de eletricidade atmosfrica do INPE, o nmero de mortes por raios maior do que por deslizamentos e enchentes. E na primavera e no vero, poca com mais tempestades, que a preocupao aumenta (...) Disponvel em: ww1.g1.globo.com/bom-dia-brasil. Acesso em:16 fev.2017. Como se pode verificar na notcia acima, os raios causam mortes e, alm disso, constantemente h outros prejuzos ligados a eles: destruio de linhas de transmisso de energia e telefonia, incndios florestais, dentre outros. As nuvens se eletrizam devido s partculas de gelo que comeam a descer muito rapidamente, criando correntes de ar bastante bruscas, o que provoca frico entre gotas de gua e de gelo, responsvel pela formao e, consequentemente, a acumulao de eletricidade esttica. Quando se acumula carga eltrica negativa demasiadamente na zona inferior da nuvem (este o caso mais comum) ocorre uma descarga eltrica em direo ao solo (que por induo eletrosttica adquiriu cargas positivas). Considere que a base de uma nuvem de tempestade, eletricamente carregada com carga de mdulo igual a ,situa-se a acima do solo. O ar mantm-se isolante at que o campo eltrico entre a base da nuvem e o solo atinja o valor de Nesse instante a nuvem se descarrega por meio de um raio que dura Considerando que o campo eltrico na regio onde ocorreu o raio seja uniforme, a energia liberada neste raio , em joules, igual a

(AFA - 2018) TEXTO PARA A PRXIMA QUESTO. FOOD SHORTAGE CAUSES, EFFECTS AND SOLUTIONS Food shortage is a serious problem facing the world and is prevalent in sub-Saharan Africa. The scarcity of food is caused by economic, environmental and social factors such as crop failure, overpopulation and poor government policies are the main cause of food scarcity in most countries. Environmental factors determine the kind of crops to be produced in a given place, economic factors determine the buying and production capacity and socio-political factors determine distribution of food to the masses. Food shortage has far reaching long and short term negative impacts which include starvation, malnutrition, increased mortality and political unrest1. There is need to collectively address the issue of food insecurity using both emergency and long term measures. Causes of food shortages There are a number of social factors causing food shortages. The rate of population increase is higher than increase in food production. The world is consuming more than it is producing, leading to decline in food stock and storage level and increased food prices due to soaring2 demand. Increased population has led to clearing of agricultural land for human settlement reducing agricultural production (Kamdor, 2007). Overcrowding of population in a given place results in urbanization of previously rich agricultural fields. Destruction of forests for human settlement, particularly tropical rain forest has led to climatic changes, such as prolonged droughts and desertification. Population increase means more pollution as people use more fuel in cars, industry, domestic cooking. The resultant effect is increased air and water pollution which affect the climate and food production. Environmental factors have greatly contributed to food shortage. Climatic change has reduced agricultural production. The change in climate is majorly caused by human activities and to some small extent natural activities. Increased combustion of fossil fuels due to increasing population through power plant, motor transport and mining of coal and oil emits green house gases which have continued to affect world climate. Deforestation of tropical forest due to human pressure has changed climatic patterns and rainfall seasons, and led to desertification which cannot support a crop production. Land degradation due to increased human activities has impacted negatively on agricultural production (Kamdor, 2007). Natural disasters such as floods, tropical storms and prolonged droughts are on the increase and have devastating impacts on food security particularly in developing countries. There are several economic factors that contribute to food shortage. Economic factors affect the ability of farmers to engage in agricultural production. Poverty situation in developing nations have reduced their capacity to produce food, as most farmers cannot afford seed and fertilizers. They use poor farming methods that cannot yield3 enough, even substantial use. Investments in agricultural research and developing are very low in developing nations. Recent global financial crisis have led to increase in food prices and reduced investments in agriculture by individuals and governments in developed nations resulting in reduced food production. Effects of food shortage There are a number of short term effects of food shortage. The impact on children, mothers and elderly are very evident as seen in malnutrition and hunger related deaths. Children succumb to hunger within short period as they cannot stand long period of starvation and they die even before the arrival of emergency assistance. There are also long term effects of food shortage. These include increase in the price of food as a result demand and supply forces. Increasing cost of food production due to the increase in fuel prices coupled with persistent drought in grain producing regions has contributed to the increase in the price of food in the world. Increase in oil price led to increase in the price of fertilizers, transportation of food and also industrial agriculture. Increasing food prices culminated in political instability and social unrest in several nations across the globe in 2007, in countries of Mexico, Cameroon, Brazil, Burkina Faso, Pakistan, Egypt and Bangladesh among other nations (Kamdor, 2007). Solution to problem of food shortage There are some solutions to the problem of food shortage. There is need to reduce production of carbon emissions and pollution to reduce the resultant climatic change through concerted and individual efforts. There is need to invest in clean energy such as solar, nuclear, and geothermal power in homes and industries, because they dont have adverse effects on the environment (Kamdor, 2007). Rich nations should help poor nations to develop and use clean and renewable energy in order to stabilize green house emissions into the atmosphere (Watson, nd). Government need to work in consultation with climatic bodies, World Bank and the UN to engage in projects aimed at promoting green environment. Conclusion Causes of food shortage are well known and can be solved if appropriate measures to solve the problem are taken and effectively implemented. Environmental causes of food shortages are changes in climatic and pollution due to human activities such overgrazing4 and deforestation which can be controlled through legislation. (Adapted from http://www.paypervids.com/food-shortage-causes- effects-solutions/Acesso em:14 fev 2017) Glossary: 1. unrest disagreement or fighting between different groups of people 2. soaring something that increases rapidly above the usual level 3. yield to supply or produce something such as profit or an amount or food 4. overgrazing excessive use of land where animals feed on grass The text conclusion seems to be

(AFA - 2018) TEXTO PARA A PRXIMA QUESTO. FOOD SHORTAGE CAUSES, EFFECTS AND SOLUTIONS Food shortage is a serious problem facing the world and is prevalent in sub-Saharan Africa. The scarcity of food is caused by economic, environmental and social factors such as crop failure, overpopulation and poor government policies are the main cause of food scarcity in most countries. Environmental factors determine the kind of crops to be produced in a given place, economic factors determine the buying and production capacity and socio-political factors determine distribution of food to the masses. Food shortage has far reaching long and short term negative impacts which include starvation, malnutrition, increased mortality and political unrest1. There is need to collectively address the issue of food insecurity using both emergency and long term measures. Causes of food shortages There are a number of social factors causing food shortages. The rate of population increase is higher than increase in food production. The world is consuming more than it is producing, leading to decline in food stock and storage level and increased food prices due to soaring2 demand. Increased population has led to clearing of agricultural land for human settlement reducing agricultural production (Kamdor, 2007). Overcrowding of population in a given place results in urbanization of previously rich agricultural fields. Destruction of forests for human settlement, particularly tropical rain forest has led to climatic changes, such as prolonged droughts and desertification. Population increase means more pollution as people use more fuel in cars, industry, domestic cooking. The resultant effect is increased air and water pollution which affect the climate and food production. Environmental factors have greatly contributed to food shortage. Climatic change has reduced agricultural production. The change in climate is majorly caused by human activities and to some small extent natural activities. Increased combustion of fossil fuels due to increasing population through power plant, motor transport and mining of coal and oil emits green house gases which have continued to affect world climate. Deforestation of tropical forest due to human pressure has changed climatic patterns and rainfall seasons, and led to desertification which cannot support a crop production. Land degradation due to increased human activities has impacted negatively on agricultural production (Kamdor, 2007). Natural disasters such as floods, tropical storms and prolonged droughts are on the increase and have devastating impacts on food security particularly in developing countries. There are several economic factors that contribute to food shortage. Economic factors affect the ability of farmers to engage in agricultural production. Poverty situation in developing nations have reduced their capacity to produce food, as most farmers cannot afford seed and fertilizers. They use poor farming methods that cannot yield3 enough, even substantial use. Investments in agricultural research and developing are very low in developing nations. Recent global financial crisis have led to increase in food prices and reduced investments in agriculture by individuals and governments in developed nations resulting in reduced food production. Effects of food shortage There are a number of short term effects of food shortage. The impact on children, mothers and elderly are very evident as seen in malnutrition and hunger related deaths. Children succumb to hunger within short period as they cannot stand long period of starvation and they die even before the arrival of emergency assistance. There are also long term effects of food shortage. These include increase in the price of food as a result demand and supply forces. Increasing cost of food production due to the increase in fuel prices coupled with persistent drought in grain producing regions has contributed to the increase in the price of food in the world. Increase in oil price led to increase in the price of fertilizers, transportation of food and also industrial agriculture. Increasing food prices culminated in political instability and social unrest in several nations across the globe in 2007, in countries of Mexico, Cameroon, Brazil, Burkina Faso, Pakistan, Egypt and Bangladesh among other nations (Kamdor, 2007). Solution to problem of food shortage There are some solutions to the problem of food shortage. There is need to reduce production of carbon emissions and pollution to reduce the resultant climatic change through concerted and individual efforts. There is need to invest in clean energy such as solar, nuclear, and geothermal power in homes and industries, because they dont have adverse effects on the environment (Kamdor, 2007). Rich nations should help poor nations to develop and use clean and renewable energy in order to stabilize green house emissions into the atmosphere (Watson, nd). Government need to work in consultation with climatic bodies, World Bank and the UN to engage in projects aimed at promoting green environment. Conclusion Causes of food shortage are well known and can be solved if appropriate measures to solve the problem are taken and effectively implemented. Environmental causes of food shortages are changes in climatic and pollution due to human activities such overgrazing4 and deforestation which can be controlled through legislation. (Adapted from http://www.paypervids.com/food-shortage-causes- effects-solutions/Acesso em:14 fev 2017) Glossary: 1. unrest disagreement or fighting between different groups of people 2. soaring something that increases rapidly above the usual level 3. yield to supply or produce something such as profit or an amount or food 4. overgrazing excessive use of land where animals feed on grass In the sentence land degradation due to increased human activities has impacted negatively on agricultural production (destacado) it is INCORRECT to state that