CLASS TEST GRADE 11. PHYSICAL SCIENCES: PHYSICS Test 1: Mechanics

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1 CLASS TEST GRADE 11 PHYSICAL SCIENCES: PHYSICS Test 1: Mechanics MARKS: 45 TIME: 1 hour INSTRUCTIONS AND INFORMATION 1. Answer ALL the questions. 2. You may use non-programmable calculators. 3. You may use appropriate mathematical instruments. 4. Number the answers correctly according to the numbering system used in this question paper. 5. Data sheets are attached for your use. 6. Wherever motivation, discussion, et cetera is required, write brief answers.

2 SECTION A QUESTION 1: ONE-WORD ANSWERS Give ONE word or term for EACH of the following descriptions. Write only the word or term next to the question number ( ). 1.1 The vector sum of all forces acting on a body. (1) 1.2 The perpendicular component of the force exerted by a surface on an object in contact with the surface. (1) [2] QUESTION 2: FALSE STATEMENTS Correct the following FALSE statements. Write the correct statement next to the question number ( ). 2.1 The velocity of a moving box on a surface cannot be constant if a constant force acts on the box. (2) 2.2 The force of attraction between two bodies in the universe is inversely proportional to the distance between their centres. (2) [4] Maskew Miller Longman, Focus on Physical Sciences Grade 11 Test 1: Mechanics Page 2 of 7

3 QUESTION 3: MULTIPLE-CHOICE QUESTIONS Choose the correct answer to the following questions. Write only the letter (A D) next to the question number ( ). 3.1 Which one of the following physical quantities has the unit kg m s 1? A force B impulse C acceleration D torque (2) 3.2 A net force is applied to a 10 kg box that is initially at rest on a horizontal surface. The graph below shows the amount of force applied over time. The velocity of the box, in m s 1,after the force has been applied is A 4 B 10 C 16 D 8 (2) [4] TOTAL SECTION A: 10 Maskew Miller Longman, Focus on Physical Sciences Grade 11 Test 1: Mechanics Page 3 of 7

4 SECTION B INSTRUCTIONS AND INFORMATION 1. The formulae and substitutions must be shown in ALL calculations. 2. Round off your answers to TWO decimal places where applicable. QUESTION 4 A police dog gets caught in a shootout. A 5 g bullet moving at 100 m s 1 strikes the dog and lodges in his shoulder. Fortunately the dog survives. The bullet undergoes uniform acceleration and penetrates his shoulder to a depth of 6 cm. Calculate: 4.1 the time taken for the bullet to stop (3) 4.2 the impulse on the shoulder (4) 4.3 the average force experienced by the dog. (3) [10] QUESTION 5 A 50 kg box is at rest on a horizontal surface. When an 80 N force is applied to the box, it slides on the surface with a constant velocity. 5.1 Draw a labelled free body diagram for the box when it is at rest moving at constant velocity. (4) 5.2 Calculate the coefficient of friction. (3) 5.3 How will the force of friction change if: an identical box is placed on top of the 50 kg box (1) the same force is applied on another 50 kg box with a larger surface area? (1) Write only INCREASES, DECREASES or STAYS THE SAME. [9] Maskew Miller Longman, Focus on Physical Sciences Grade 11 Test 1: Mechanics Page 4 of 7

5 QUESTION 6 A learner gave the following argument. A horse pulls on a cart. By Newton s third law of motion, the cart pulls back on the horse with a force equal to that exerted by the horse on the cart. The sum of the forces is zero. Therefore it follows that it is not possible for the horse to accelerate the cart. Is the learner s argument correct? Explain fully. [4] QUESTION 7 A man plans to use a 2 metre crowbar to lift a rock by putting a pivot 0,8 m from the rock. One end of the crowbar will be under the rock and he will push down on the other end with a force of 400 N. The mass of the rock is 50 kg. 7.1 Will the man be able to move the rock? Show how you worked out your answer. (4) 7.2 The man s daughter says that she can move the rock although her force on the other end is only 200 N. Explain how this is possible. (4) [8] QUESTION 8 An astronaut lands on a new planet. The new planet s mass is half that of the Earth and the new planet s radius is half that of the Earth. If he weighs 500 N on Earth, what will the force of gravity be on him on the new planet? [4] TOTAL SECTION B: 35 GRAND TOTAL: 45 Maskew Miller Longman, Focus on Physical Sciences Grade 11 Test 1: Mechanics Page 5 of 7

6 DATA FOR PHYSICAL SCIENCES GRADE 11 PHYSICS PHYSICAL CONSTANTS NAME SYMBOL VALUE Acceleration due to gravity g 9,8 m s 2 Speed of light in a vacuum c 3, m s 1 Gravitational constant G 6, N m 2 kg 2 Coulomb s constant k 9, N m 2 C 2 Charge on electron e 1, C Electron mass m e 9, kg Permittivity of free space ε 0 8, F m 1 FORMULAE MOTION v f = v i + aδt v f 2 = v i 2 + 2aΔx Δx = v i Δt = 1 2 aδt2 Δx = ( v + v f i 2 ) Δt FORCE F net = ma p = mv F = Gm m 1 2 FΔt = Δp = mv mu r 2 μ s = f s(max) N μ = f k k N WEIGHT AND MECHANICAL ENERGY F g = mg U = E p = mgh K = E k = 1 2 mv2 Printed with permission, National Department of Education Maskew Miller Longman, Focus on Physical Sciences Grade 11 Test 1: Mechanics Page 6 of 7

7 WAVES, LIGHT AND SOUND v = f λ or v = v λ T = 1 or T = 1 f v ELECTROSTATICS F = kq Q 1 2 ( k = 9,0 10 r 2 9 N m 2 C-2 ) E = F q E = kq r 2 ( k = 9, N m 2 C -2 ) E = V d V = W Q W = QEs U = kq Q 1 2 r ( k = 9,0 109 N m 2 C -2 ) C = Q V C = e 0 A d ELECTROMAGNETISM e = N ΔΦ Δt V s = N s V p N p Φ = BA F = qvb CURRENT ELECTRICITY I = Q Δt emf = I(R + r) R = V I R = r 1 + r 2 + r = 1 R r r r + 3 Printed with permission, National Department of Education Maskew Miller Longman, Focus on Physical Sciences Grade 11 Test 1: Mechanics Page 7 of 7