Cadernos
Impulso sob a ação de uma força resultante
Um móvel de massa 100 kg inicialmente em repouso, move-se sob a ação de uma força resultante, constante, de intensidade 500 N durante 4 s A energia cinética adquirida pelo móvel, no instante t=4s em joule (J) é:
Questões relacionadas
- Biologia | 12.8 Impactos Ambientais
A figura precedente ilustra um ciclo de sustentabilidade que envolve o processo de biodigestão. Um biodigestor geralmente é alimentado por uma lama composta de restos de alimentos e fezes de animais, acrescidos de água. Dentro do aparelho, esses detritos entram em decomposição pela ação de bactérias anaeróbicas. Durante esse processo, o material orgânico acaba convertido em gás (principalmente metano, CH4), que é utilizado como combustível em fornos e fogões ou geradores de energia elétrica. O resíduo sólido que sobra no biodigestor também pode ser aproveitado como fertilizante. O ciclo de sustentabilidade mostrado envolve os processos naturais descritos a seguir.
I Na fotossíntese, o dióxido de carbono (CO2) reage com a água (H2O), para formar glicose (C6H12O6) e gás oxigênio (O2), através do consumo de energia da luz solar.
II Na respiração, há extração de energia, durante a oxidação da glicose com O2, para formar CO2 e H2O.
III Na biodigestão ou fermentação, pode ocorrer o reaproveitamento de detritos para gerar gás e adubo, também chamados de biogás e biofertilizante.
As reações apresentadas a seguir representam, respectivamente, a biodigestão anaeróbica da glicose e a combustão completa do metano.
C6H12O6(s) → 3CH4(g) + 3CO2(g)
CH4(g) + 2O2(g) → CO2(g) + 2H2O(l)
A partir das informações apresentadas, julgue o item seguinte
Apesar de ser uma fonte de energia renovável, o biogás tem alto impacto poluidor para o meio ambiente, em razão dos resíduos que gera.
- Língua Inglesa | 1.4 Reading Strategies
Military Officers Face a New Evaluation
Gen. Martin E. Dempsey, the chairman of the Joint Chiefs of Staff, is leading important changes following recent scandals involving high-ranking officers. This is part of training and development programs for generals and admirals. They will include new courses to train the security detail, executive staffs and even the spouses of senior officers.
Saying he was disturbed about the misconduct issues, General Dempsey said that evaluations of top officers needed to go beyond the traditional assessment of professional performance by superior officers alone. He said that he had decided the changes were necessary “to assess both competence and character in a richer way”.
“You can have someone of incredible character who can’t lead their way out of a forward operating base because they don’t have the competence to understand the application of military power, and that doesn’t do me any good”, General Dempsey said. “Conversely, you can have someone who is intensely competent in the skills of the profession, but doesn’t live a life of character. And that doesn’t do me any good.”
General Dempsey said that regular professional reviews would be transformed from top-down assessments to the kind of “360-degree performance evaluation”, which includes feedback from subordinates, peers and superiors. For the new training programs, he said that while it may be impossible to prevent infractions, “most officers need to be reminded of the rules and regulations on a routine basis”.
Teams of inspectors will observe and review the procedures of commanders and their staffs. The inspections will not be punitive, but will provide a “periodic opportunity for general officers to understand whether, from an institutional perspective, we think they are inside or outside the white lines”, he said. In addition, new programs will be instituted to ensure that a commander’s staff, and a spouse, are fully aware of military regulations.
“In my 39 years in the military, I have learned that you are not a profession just because you say you are. You have to earn it and re-earn it and re-evaluate it from time to time”, General Dempsey said.
Adapted from www.nytimes.com/2013/04/14/us
According to the text, a 360-degree performance evaluation (paragraph 4)
- Inglês - Fundamental | Não Possui Tópico Definido
Look at this schedule.
Daily camp schedule
Monday, Tuesday Thursday, Friday
Wednesday
Saturday
Sunday
7.00 - 8.30
Rise and shine /Breakfast
Rise and shine /Breakfast
Rise and shine /Breakfast
Rise and shine /Breakfast
8.30 - 12.00
English lessons
English lessons
Full day excursion
Laundry
12.00 - 13.00
Lunch
Lunch
Full day excursion
Lunch
13.00 - 15.15
Cultural workshops
Half day excursion
Full day excursion
Outdoor activities
15.15 -15.45
Wash hands and make plans
Half day excursion
Full day excursion
Outdoor activities
15.45 - 17.00
Pool, beach, sport group practice or competition
Half day excursion
Full day excursion
Pool, beach, sport group practice or competition
17.00 - 18.30
Dinner
Dinner
Dinner
Dinner
18.30 - 20.00
Homework preparation
Homework preparation
Full day excursion
Pool, beach, sport group practice or competition
20.00 - 22.00
Party time, disco, talent show etc.
Party time, disco, talent show etc.
Party time, disco, talent show etc.
Party time, disco, talent show etc.
22.00
Kids to bed
Kids to bed
Kids to bed
Kids to bed
23.00
Juniors and seniors to bed
Juniors and seniors to bed
Juniors and seniors to bed
Juniors and seniors to bed
Available at: <www.oliver-it.com/daily_camp_schedule/>. Accessed on: March 01, 2014.
Complete the board with information from the schedule.
Activity Time
Breakfast
Activities
Dinner
Bed for Kids
- Inglês - Fundamental | Não Possui Tópico Definido
. Read the text.
World Population Growth, 1950–2050
For the last 50 years, world population multiplied more rapidly than ever before, and more rapidly than it is projected to grow in the future. In 1950, the world had 2.5 billion people; and in 2005, the world had 6.5 billion people. By 2050, this number could rise to more than 9 billion.
World population expanded to about 300 million by A.D. 1 and continued to grow at a moderate rate. But after the start of the Industrial Revolution in the 18th century, living standards rose and widespread famines and epidemics diminished in some regions. Population growth accelerated. The population climbed to about 760 million in 1750 and reached 1 billion around 1800.
World population growth accelerated after World War II, when the population of less developed countries began to increase dramatically. After millions of years of extremely slow growth, the human population indeed grew explosively, doubling again and again; a billion people were added between 1960 and 1975; another billion were added between 1975 and 1987. Throughout the 20th century each additional billion has been achieved in a shorter period of time. Human population entered the 20th century with 1.6 billion people and left the century with 6.1 billion.
The growth of the last 200 years appears explosive on the historical timeline. The overall effects of this growth on living standards, resource use, and the environment will continue to change the world landscape long after.
The more developed countries in Europe and North America, as well as Japan, Australia, and New Zealand, are growing by less than 1 percent annually. Population growth rates are negative in many European countries, including Russia (-0.5%), Estonia (-0.4%), Hungary (-0.3%), and Ukraine (-0.8%). If the growth rates in these countries continue to fall below zero, population size would slowly decline. As the chart "World Population Growth, 1950–2050" shows, population increase in more developed countries is already low and is expected to stabilize.
Available at: http://www.prb.org/Educators/TeachersGuides/HumanPopulation/PopulationGrowth.aspx
Accessed on May 25, 2010.
Complete the sentences.
A) If the population growth continues to increase, __________________________________________ .
B) If less developed countries don’t set birth control policies, _________________________________.
C) If population growth rates in more developed countries continue to fall, _______________________.
D) If population growth rates in less developed countries continue to double,
- Espanhol - Fundamental | 3.06 Indefinidos y Numerales (Indefinidos e Numerais)
Marca o pronome indefinido que completa a oração abaixo.
“Tenemos __________ cosas que hablar esa noche”
