1. A 50-kg astronaut ejects g of gas from propulsion pistol at a velocity of 50m/s. What is his resulting velocity?
2. Two 0.5 kg balls approach each other with the same speed of 1.0 m/s. What is the total momentum of the system before collision?
3. Using the same problem on no. 2 if there is no external force acting on a system, what is the total momentum of the system after collision
Answers
Explanation:
Science (from the Latin word scientia, meaning "knowledge")[1] is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe.[2][3][4]
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The earliest roots of science can be traced to Ancient Egypt and Mesopotamia in around 3000 to 1200 BCE.[5][6] Their contributions to mathematics, astronomy, and medicine entered and shaped Greek natural philosophy of classical antiquity, whereby formal attempts were made to provide explanations of events in the physical world based on natural causes.[5][6] After the fall of the Western Roman Empire, knowledge of Greek conceptions of the world deteriorated in Western Europe during the early centuries (400 to 1000 CE) of the Middle Ages,[7] but was preserved in the Muslim world during the Islamic Golden Age.[8] The recovery and assimilation of Greek works and Islamic inquiries into Western Europe from the 10th to 13th century revived "natural philosophy",[7][9] which was later transformed by the Scientific Revolution that began in the 16th century[10] as new ideas and discoveries departed from previous Greek conceptions and traditions.[11][12][13][14] The scientific method soon played a greater role in knowledge creation and it was not until the 19th century that many of the institutional and professional features of science began to take shape;[15][16][17] along with the changing of "natural philosophy" to "natural science."[18]
Modern science is typically divided into three major branches[19] that consist of the natural sciences (e.g., biology, chemistry, and physics), which study nature in the broadest sense; the social sciences (e.g., economics, psychology, and sociology), which study individuals and societies;[20][21] and the formal sciences (e.g., logic, mathematics, and theoretical computer science), which deal with symbols governed by rules.[22][23] There is disagreement,[24][25][26] however, on whether the formal sciences actually constitute a science as they do not rely on empirical evidence.[27][25] Disciplines that use existing scientific knowledge for practical purposes, such as engineering and medicine, are described as applied sciences.[28][29][30][31][32]
New knowledge in science is advanced by research from scientists who are motivated by curiosity about the world and a desire to solve problems.[33][34] Contemporary scientific research is highly collaborative and is usually done by teams in academic and research institutions,[35] government agencies, and companies.[36] The practical impact of their work has led to the emergence of science policies that seek to influence the scientific enterprise by prioritizing the development of commercial products, armaments, health care, public infrastructure, and environmental protection.
History
Branches of science
Scientific research
Scientific community
Science and the public
"Science and society" redirects here. For the academic journal, see Science & Society. For the study of science as a social activity, see Sociology of scientific knowledge.
Science policy
Main articles: Science policy, History of science policy, and Economics of science
The United Nations Global Science-Policy-Business Forum on the Environment in Nairobi, Kenya (2017)
Science policy is an area of public policy concerned with the policies that affect the conduct of the scientific enterprise, including research funding, often in pursuance of other national policy goals such as technological innovation to promote commercial product development, weapons development, health care, and environmental monitoring. Science policy also refers to the act of applying scientific knowledge and consensus to the development of public policies. Science policy thus deals with the entire domain of issues that involve the natural sciences. In accordance with public policy being concerned about the well-being of its citizens, science policy's goal is to consider how science and technology can best serve the public.
State policy has influenced the funding of public works and science for thousands of