This physics problem tests your understanding of fundamental physical laws and their applications. The step-by-step solution below breaks down the problem using relevant equations and physical reasoning.
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Hey DOLLAR — ready when you are. Here are the solutions to the questions: 1. a) Two ways by which humans could be protected from harmful effects of radioactivity: • Shielding: Using materials like lead, concrete, or thick steel to absorb radiation. • Distance: Increasing the distance from the radioactive source, as radiation intensity decreases with distance. • Time: Minimizing the duration of exposure to radioactive sources. b) Three uses of radioisotopes: • Medical diagnosis and treatment: Used as tracers to diagnose diseases (e.g., PET scans) or in radiotherapy to treat cancer. • Sterilization: Used to sterilize medical equipment and food products by killing bacteria and other microorganisms. • Carbon dating: Used to determine the age of ancient artifacts and geological formations. • Industrial applications: Used as tracers to detect leaks in pipes or to measure the thickness of materials. 2. Five effects of climate change on humans: • Increased frequency and intensity of extreme weather events, such as floods, droughts, heatwaves, and storms, leading to loss of life and property. • Food insecurity due to disruptions in agricultural productivity, affecting crop yields and livestock. • Spread of vector-borne diseases (e.g., malaria, dengue fever) as warmer temperatures expand the geographical range of disease-carrying insects. • Displacement of populations due to rising sea levels, desertification, and extreme weather, leading to migration and potential conflicts. • Respiratory and cardiovascular problems from increased air pollution and allergens, exacerbated by heatwaves and wildfires. 3. a) What are alkanoates? Alkanoates are a class of organic compounds known as esters, which are derived from an alkanoic acid (carboxylic acid) and an alcohol. They typically have the general formula RCOOR', where R and R' are alkyl groups. b) Three uses of alkanoates: • Flavorings and fragrances: Many alkanoates have pleasant, fruity smells and are used in food flavorings and perfumes. • Solvents: They are effective solvents for many organic compounds, used in paints, varnishes, and glues. • Plasticizers: Used to make plastics more flexible and durable. 4. a) Explain the term weathering. Weathering is the process by which rocks, soil, and minerals are broken down into smaller pieces or altered chemically through contact with the Earth's atmosphere, water, and biological organisms. It does not involve the removal of the weathered material. b) Three ways of maintaining soil fertility on a sloppy land: • Terracing: Creating level steps or platforms on slopes to reduce water runoff and soil erosion, allowing for better water retention and nutrient preservation. • Contour plowing: Plowing across the slope, following the contours of the land, to create furrows that trap water and prevent soil erosion. • Cover cropping: Planting non-cash crops (cover crops) between main crops or during fallow periods to protect the soil from erosion, add organic matter, and improve nutrient cycling. • Agroforestry: Integrating trees and shrubs into agricultural systems to stabilize soil, reduce erosion, and enhance biodiversity. 5. a) Two reasons why genetic variation is important in living organisms: • Adaptation: Genetic variation provides the raw material for natural selection, allowing populations to adapt to changing environmental conditions and survive. • Disease resistance: A diverse gene pool increases the likelihood that some individuals in a population will have resistance to new diseases, protecting the population from widespread epidemics. b) Three examples of genetic variations in humans: • Eye color (e.g., blue, brown, green) • Blood type (e.g., A, B, AB, O) • Height • Skin color • Hair texture (e.g., straight, wavy, curly) 6. a) State Archimedes' principle. Archimedes' principle states that the buoyant force (upthrust) on an object submerged in a fluid is equal to the weight of the fluid displaced by the object. b) Calculate the upthrust of the sea water on the boat. Step 1: Identify the given values. Volume of boat, V = 200 m^3 Density of sea water, = 10.30 kg m^-3 Acceleration due to gravity, g = 10 m s^-2 Step 2: Apply the formula for upthrust. The upthrust (F_b) is given by the formula: F_b = × V × g Step 3: Substitute the values into the formula and calculate. F_b = 10.30 kg m^-3 × 200 m^3 × 10 m s^-2 F_b = 20600 N The upthrust of the sea water on the boat is 20600 N. That's the end of the paper! Send me the next one 📸