I read this background article the other day: The classical explanation of gravity is that a force of attraction acts at a distance between two objects and the magnitude of the force is directly proportional to each of the masses and inversely proportional to the square of the distance between the objects. The objects move toward each other due to this force of attraction. Einstein's new concept of gravity states that matter (mass) causes the space around the matter to curve and also distorts time. A straight line through this curved space would also be curved in order to be a straight line. I am facing a new situation today: Rob is an amateur astronomer. Recently, he detected four asteroids, asteroid A, asteroid B, asteroid C, and asteroid D. Asteroid A and asteroid B are of the same mass, but asteroid A is farther from the earth than asteroid B. Asteroid C and asteroid D are at the same distance form the earth, but asteroid C has more mass than asteroid D. He also figured out that all of these asteroids have less mass than earth. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: In classical theory, which asteroid would have stronger garvitational pull from earth, asteroid A or asteroid B?
Ans: asteroid B

I read this background article the other day: Similar to the results of a negatively charged rod, if a positively charged rod is brought near the knob of a neutral electroscope, it will attract some electrons up from the leaves onto the knob. That process causes both of the leaves to be positively charged (excess protons), and the leaves will diverge. If the positively charged rob is actually touched to the knob, the rob will remove some electrons and then when the rob is removed, the electroscope will remain positively charged. This is a permanent positive charge. I am facing a new situation today: Jim's dad is a scientist. While his dad is out working he goes to the lab in the basement and find an electroscope. The electroscope is currently in a neutral state. He then grabs a nearby rod that is positively charged and moves it near the knob of the electroscope. Fascinated he sees the leaves of the electroscope move apart from each other. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Given the electroscope is now positively charged, is this a permanent or temporary charge?
Ans: permanent

I read this background article the other day: The Human Immunodeficiency Virus ( HIV ) is the virus that causes Acquired Immunodeficiency Syndrome ( AIDS ). Most researchers believe that the HIV originated in sub-Saharan Africa during the 20th century. HIV is transmitted by sexual contact and by contact with infected bodily fluids, such as blood, semen, breast milk, and vaginal secretions. It is also passed from mother to fetus. HIV is now a pandemic , with an estimated (as of 2008) 38.6 million people now living with the disease worldwide. It is estimated that AIDS has killed more than 25 million people since it was first recognized in 1981. For further information about HIV/AIDS, see the CDC (Centers for Disease Control and Prevention) web site at http://www.cdc.gov/hiv/resources/factsheets/ . I am facing a new situation today: Two neighboring countries had health epidemics. While Ghana had a measles problem, Niger had a very serious HIV problem that seemed to get out of control. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which country had fewer people at risk of getting AIDS?
Ans: Ghana

I read this background article the other day: Rainfall in an area is important because it influences the rate of weathering. More rain means that more rainwater passes through the soil. The rainwater reacts chemically with the particles. The top layers of soil are in contact with the freshest water, so reactions are greatest there. High rainfall increases the amount of rock that experiences chemical reactions. High rainfall may also carry material away. This means that new surfaces are exposed. This increases the rate of weathering. I am facing a new situation today: John was studying about the history of Sahara desert. He was amazed to find that ten thousand years ago there were plenty of rainfall in that region. He labeled that era as era A. Then he found that rainfall deceased in the region about eight thousand years ago. He labeled that era as era B. He was wondering how that change in rainfall might have helped emerge the Egyptian civilization. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Would era A see higher or lower rate of weathering than era B?
Ans: higher