9702_s12_qp_23
A paper of Physics, 9702
Questions:
7
Year:
2012
Paper:
2
Variant:
3
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1
Examiner s Use Explain the differences between the quantities distance and displacement. State Newton’s first law. Two tugs pull a tanker at constant velocity in the direction XY, as represented in . 25.0° T1 T2 Y X tanker tug 2 tug 1 15.0° Tug 1 pulls the tanker with a force T1 at 25.0° to XY. Tug 2 pulls the tanker with a force of T2 at 15.0° to XY. The resultant force R due to the two tugs is 25.0 × 103 N in the direction XY. By reference to the forces acting on the tanker, explain how the tanker may be described as being in equilibrium. For Examiner’s Use 1. Complete to draw a vector triangle for the forces R, T1 and T2. 25.0 × 103 N R 2. Use your vector triangle in to determine the magnitude of T1 and of T2. T1 = N T2 = N
4. Forces, density and pressure  →  4.2. Equilibrium of forces
3. Dynamics  →  3.1. Momentum and Newton’s laws of motion
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2
For Examiner’s Use A motor drags a log of mass 452 kg up a slope by means of a cable, as shown in . cable 10.0 m 14.0° start and finish position of log S P motor The slope is inclined at 14.0° to the horizontal. Show that the component of the weight of the log acting down the slope is 1070 N. The log starts from rest. A constant frictional force of 525 N acts on the log. The log accelerates up the slope at 0.130 m s–2. Calculate the tension in the cable. tension = N For Examiner’s Use The log is initially at rest at point S. It is pulled through a distance of 10.0 m to point P. Calculate, for the log, 1. the time taken to move from S to P, time = s 2. the magnitude of the velocity at P. velocity = m s–1 The cable breaks when the log reaches point P. On , sketch the variation with time t of the velocity v of the log. The graph should show v from the start at S until the log returns to S. v t
2. Kinematics  →  2.1. Equations of motion
3. Dynamics  →  3.2. Non-uniform motion
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4
For Examiner’s Use Define electric field strength. A uniform electric field is produced by applying a potential difference of 1200 V across two parallel metal plates in a vacuum, as shown in . 1200 V 14 mm P metal plates The separation of the plates is 14 mm. A particle P with charge 3.2 × 10–19 C and mass 6.6 × 10–27 kg starts from rest at the lower plate and is moved vertically to the top plate by the electric field. Calculate the electric field strength between the plates, electric field strength = V m–1 the work done on P by the electric field, work done = J the gain in gravitational potential energy of P, gain in potential energy = J For Examiner’s Use the gain in kinetic energy of P, gain in kinetic energy = J the speed of P when it reaches the top plate. speed = m s–1
18. Electric fields  →  18.2. Uniform electric fields
18. Electric fields  →  18.5. Electric potential
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5
For Examiner’s Use State Kirchhoff’s first law. Kirchhoff’s first law is linked to the conservation of a certain quantity. State this quantity. A variable resistor of resistance R is used to control the current in a circuit, as shown in . G 20 V 12 V 0.50 Ω – + 0.10 Ω R The generator G has e.m.f. 20 V and internal resistance 0.50 Ω. The battery has e.m.f. 12 V and internal resistance 0.10 Ω. The current in the circuit is 2.0 A. Apply Kirchhoff’s second law to the circuit to determine the resistance R. R = Ω Calculate the total power generated by G. power = W For Examiner’s Use Calculate the power loss in the total resistance of the circuit. power = W The circuit is used to supply energy to the battery from the generator. Determine the efficiency of the circuit. efficiency =
10. D.C. circuits  →  10.2. Kirchhoff’s laws
9. Electricity  →  9.2. Potential difference and power
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6
For Examiner’s Use Monochromatic light is diffracted by a diffraction grating. By reference to this, explain what is meant by diffraction, coherence, superposition. A parallel beam of red light of wavelength 630 nm is incident normally on a diffraction grating of 450 lines per millimetre. Calculate the number of diffraction orders produced. number of orders = The red light in is replaced with blue light. State and explain the effect on the diffraction pattern.
8. Superposition  →  8.4. The diffraction grating
8. Superposition  →  8.2. Diffraction
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