Science (Mining) (SMI181Q): Exam 20 2019, questions and answers Science (Mining) (University of South Africa)

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• This examination paper consists of thirteen (13) pages. • The paper consists of two sections; Section A (30%) and Section B (70%). • Answer Section A (Multiple choice) on the examination mar... k reading sheet. • Answer Section B (Written solutions) in the examination answer book. • Show all steps in carrying out the calculations. • The mark allocation for each question is indicated in square brackets to the right. • The information given at the end of Section B may be used without proof. SMI181Q Oct/Nov 2019 Section B: Written Solution [70 marks ] 1. A superhero flies from the top of a tall building following the path shown in the figure. If he continues in a straight line for 100 m, Determine horizontal and vertical components of the displacement. [4] Solution: Horizontal component Sx Vertical component Sy 2. A ball is thrown straight up with a speed of 36 m/s. a. How long does it take the ball to reach the maximum height? (3) Solution: SMI181Q Oct/Nov 2019 b. Determine the maximum height reached by the ball. (2) Solution: or s ut 1 at2 2 s (36)(3, 67) 1 ( 9, 8)(3, 67)2 2 s 132,12 ( 65, 99) s 66,12 m c. How long does it take return to its starting point? (2) Solution: downwards Total time t=7,34 s [7] 3. Two blocks of m1=3.50 kg and m2 = 8.00 kg are connected by a string of negligible mass that passes over a frictionless pulley as shown in the figure below. The inclines are frictionless. SMI181Q Oct/Nov 2019 a. Draw the free body diagrams for each mass. (4) b. Determine the magnitude of the acceleration. (2) SMI181Q Oct/Nov 2019 c. Calculate the tension on the string. (3) 4. A car is moving with a speed of 32.0 m/s. The driver sees an accident ahead and slams on the brakes, giving the car a deceleration of 3.50 m/s2. How far does the car travel after the driver put on the brakes before it comes to a stop? Solution: [4] 4 [Turn Over ] SMI181Q Oct/Nov 2019 5. A silver wire is 5.9 m long and 0.49 mm in diameter. If the resistivity of the wire is   1.59108  m , Determine the resistance of the wire. [4] Solution: 6. Convert 180o to radians. [2] 7. A compact disc rotates at 300 revolutions per minute. Determine its angular speed in rad/s. [4] 5 [Turn Over ] SMI181Q Oct/Nov 2019 8. 2.67 g of Na2CO3 is dissolved in water and made up with water to a volume of 250 cm3. a. Calculate the molar mass of Na2CO3. (3) Na2CO3 b. Deteremine the concentration. (2) [5] 9. A sample of argon gas at 520 mm Hg expands from 0.150 L to 0.300 L. If the temperature remains constant, what is the final pressure in mm Hg? Solution: 6 [Turn Over ] SMI181Q Oct/Nov 2019 OR (Please choose the one that the student scored more marks on) Determine the pH of an aqueous solution if the [H+] = 0.000001M [4] Solution: pH Log[H ] Log[0.000001] [ 6] 6 10. In the following reaction; Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s) a. Define a reducing agent? (2) Solution: Reducing agent: a substance that tends to bring about reduction by being oxidized and losing electrons b. Which metal is reduced? (2) c. Which metal is oxidised? (2) [6] 11. What is the IUPAC name for: CH3-CH2-CH2-CH2-CH2-CH3? [2] 12. A number of resistors are connected across points A and B as shown in the figure below. Determine the equivalent resistance between points A and B. [8] 7 [Turn Over ] SMI181Q Oct/Nov 2016 Solution: Series resistors: 8 [Turn Over ] SMI181Q Oct/Nov 2019 13. A small object is located 30.0 cm in front of a concave mirror with a radius of curvature of 40.0 cm. a. Calculate the focal length. (2) b. Determine the image position. (3) c. Is the image upright or inverted? Explain. (2) The image is inverted due to negative sign of magnification. [7] 14. Light enters a container of benzene at an angle of 43o to the normal; the refracted beam makes an angle of 27o with the normal. Calculate the refractive index of benzene. [4] Solution: ©Unisa 2019 10 [Show More]

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