General Science: Content Knowledge 5435 Questions and Answers Rated A+

General Science: Content Knowledge 5435 Questions and Answers Rated A+ A 10 kg cart is rolling along the surface shown in the figure above. What is the minimum kinetic energy of the cart at the base of the hill if it is going to be able to roll to the top of the upper level? (Assume g = 10 m/s2 g equals, 10 meters per second squared.) Option (D) is correct. By energy conservation, the sum of the cart's kinetic energy and potential energy is a constant (assuming negligible energy loss due to friction and air resistance). As the cart moves up the hill, its kinetic energy will decrease and its potential energy will increase. If the cart just reaches the top of the hill, then the cart will be at rest at the top of the hill and will have only potential energy at that point; that is, its initial kinetic energy at the base of the hill will have been converted entirely into potential energy at the top of the hill. Thus the minimum kinetic energy of the cart is equal to 10 kg × 10 m/s2 × 4.0 m = 400 joules1. A ball is thrown in a horizontal direction. The ball is released at a vertical height of 6 feet and with an initial speed along the horizontal direction only, as shown in figure IRoman numeral 1. At the same time, an identical ball is dropped from rest from a vertical height of 6 feet. Which of the following best describes what happens subsequently? (Assume that air friction is negligible) Option (D) is correct. In the absence of air resistance, both balls fall vertically with the same gravitational acceleration and will hit the ground at the same time. A newly emerging threat to human health is the West Nile virus, which is carried by mosquitoes. Of the following suggestions, which would provide the best protection from the West Nile virus? C.Eliminating standing water around the home Mosquitoes breed in standing water. Eliminating the breeding sites of mosquitoes can reduce the local population of mosquitoes, thereby decreasing the likelihood of being bitten by a mosquito carrying the West Nile virus. A phagocytic white blood cell will most likely have more of which of the following organelles than a muscle cell will? B.Lysosomes Phagocytic cells engulf and digest large particulate materials (e.g., destruction of bacteria by macrophages or neutrophils). Lysosomes are organelles that contain hydrolytic enzymes and function in intracellular digestion. A respiratory control center is located in which of the following structures? C.Medulla oblongata The neurons primarily responsible for regulating breathing are located in the medulla oblongata, near the base of the brain stem. Neural circuits in the respiratory control center detect stretching of the lungs and regulate the degree of lung expansion during inhalation. Neurons in the medulla also use the pH of the blood as an indicator of the necessary depth and rate of breathing. Increased metabolic activity causes an increase in blood CO2 , which dissociates into HCO3- and H+ . This causes a decrease in the pHp H of the blood and of the cerebrospinal fluid that bathes the central nervous system. A sample of liquid water of a certain mass at 20°C and 1 atm20 degrees Celsius and one atmosphere has a volume of 1,000 mL1,000 milliliters. Which of the following is the most likely volume of a water sample with the same mass at 80°C and 1 atm? C.1,027 mL The volume of liquid water generally increases in very small increments with increasing temperatures. Since the water is in the liquid state and not in the gaseous state, the volume of the sample at 80°C is most likely 1,027 mL, only slightly larger than the volume of the sample at 20°C. A student placed 20 radish seeds on a damp paper towel in a petri dish and placed the dish under a fluorescent light. After 48 hours, all the seeds had germinated. In order for the student to draw a valid conclusion about the effect of water on seed germination, which of the following should also have been included in the investigation? In order to draw a valid conclusion about the effect of water on seed germination, the student should have included a control experiment, a second dish with a dry paper towel, in the investigation. The only experimental variable should be the presence or absence of water. The control variables, light and temperature, should be the same for both dishes. C.A second dish with a dry, rather than damp, paper towel should have been used. A thermometer inserted into a solution has a mercury level of just a bit less than halfway between the markings for 22.4oC22 point 4 degrees Celsius and 22.5oC22 point 5 degrees Celsius. To represent the correct number of significant figures, the temperature of the solution should be recorded as C. 22.44 For any marked measuring device, one place beyond the numerical place of the marking is estimated, and this determines the correct number of significant figures. If the thermometer is marked to 0.1°Czero point one degrees Celsius, the hundredth place should be estimated and the