9702_s19_qp_22
A paper of Physics, 9702
Questions:
6
Year:
2019
Paper:
2
Variant:
2
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1
The diameter d of a cylinder is measured as 0.0125 m ± 1.6%. Calculate the absolute uncertainty in this measurement. absolute uncertainty = m The cylinder in stands on a horizontal surface. The pressure p exerted on the surface by the cylinder is given by p = d W π . The measured weight W of the cylinder is 0.38 N ± 2.8%. Calculate the pressure p. p = N m−2 Determine the absolute uncertainty in the value of p. absolute uncertainty = N m−2
1. Physical quantities and units  →  1.3. Errors and uncertainties
4. Forces, density and pressure  →  4.3. Density and pressure
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2
State Newton’s second law of motion. A car of mass 850 kg tows a trailer in a straight line along a horizontal road, as shown in . trailer tow-bar car mass 850 kg horizontal road The car and the trailer are connected by a horizontal tow-bar. The variation with time t of the velocity v of the car for a part of its journey is shown in . t / s v / m s–1 Calculate the distance travelled by the car from time t = 0 to t = 10 s. distance = m At time t = 10 s, the resistive force acting on the car due to air resistance and friction is 510 N. The tension in the tow-bar is 440 N. For the car at time t = 10 s: 1. use to calculate the acceleration acceleration = m s−2 2. use your answer to calculate the resultant force acting on the car resultant force = N 3. show that a horizontal force of 1300 N is exerted on the car by its engine 4. determine the useful output power of the engine. output power = W A short time later, the car in is travelling at a constant speed and the tension in the tow-bar is 480 N. The tow-bar is a solid metal rod that obeys Hooke’s law. Some data for the tow-bar are listed below. Young modulus of metal = 2.2 × 1011 Pa original length of tow-bar = 0.48 m cross-sectional area of tow-bar = 3.0 × 10−4 m2 Determine the extension of the tow-bar. extension = m The driver of the car in sees a pedestrian standing directly ahead in the distance. The driver operates the horn of the car from time t = 15 s to t = 17 s. The frequency of the sound heard by the pedestrian is 480 Hz. The speed of the sound in the air is 340 m s−1. Use to calculate the frequency of the sound emitted by the horn. frequency = Hz
3. Dynamics  →  3.1. Momentum and Newton’s laws of motion
6. Deformation of solids  →  6.2. Elastic and plastic behaviour
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3
State what is meant by the centre of gravity of a body. A uniform square sign with sides of length 0.68 m is fixed at its corner points A and B to a wall. The sign is also supported by a wire CD, as shown in . wire 54 N 0.68 m 0.68 m 35° D C sign wall B A E W (not to scale) The sign has weight W and centre of gravity at point E. The sign is held in a vertical plane with side BC horizontal. The wire is at an angle of 35° to side BC. The tension in the wire is 54 N. The force exerted on the sign at B is only in the vertical direction. Calculate the vertical component of the tension in the wire. vertical component of tension = N Explain why the force on the sign at B does not have a moment about point A. By taking moments about point A, show that the weight W of the sign is 150 N. Calculate the total vertical force exerted by the wall on the sign at points A and B. total vertical force = N The sign in is held together by nuts and bolts. One of the nuts falls vertically from rest through a distance of 4.8 m to the pavement below. The nut lands on the pavement with a speed of 9.2 m s−1. Determine, for the nut falling from the sign to the pavement, the ratio change in gravitational potential energy final kinetic energy . ratio =
4. Forces, density and pressure  →  4.1. Turning effects of forces
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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4
For a progressive water wave, state what is meant by: displacement amplitude. Two coherent waves X and Y meet at a point and superpose. The phase difference between the waves at the point is 180°. Wave X has an amplitude of 1.2 cm and intensity I. Wave Y has an amplitude of 3.6 cm. Calculate, in terms of I, the resultant intensity at the meeting point. intensity = Monochromatic light is incident on a diffraction grating. Describe the diffraction of the light waves as they pass through the grating. A parallel beam of light consists of two wavelengths 540 nm and 630 nm. The light is incident normally on a diffraction grating. Third-order diffraction maxima are produced for each of the two wavelengths. No higher orders are produced for either wavelength. Determine the smallest possible line spacing d of the diffraction grating. d = m The beam of light in is replaced by a beam of blue light incident on the same diffraction grating. State and explain whether a third-order diffraction maximum is produced for this blue light.
7. Waves  →  7.1. Progressive waves
8. Superposition  →  8.4. The diffraction grating
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5
State Kirchhoff’s second law. A battery of electromotive force (e.m.f.) 5.6 V and internal resistance r is connected to two external resistors, as shown in . r 5.6 V V The reading on the voltmeter is 4.8 V. Calculate: 1. the combined resistance of the two resistors connected in parallel combined resistance = Ω 2. the current in the battery. current = A Show that the internal resistance r is 2.5 Ω. Determine the ratio power dissipated by internal resistance r total power produced by battery . ratio = The battery in is now connected to a battery of e.m.f. 7.2 V and internal resistance 3.5 Ω. The new circuit is shown in . 5.6 V 7.2 V 2.5 3.5 Determine the current in the circuit. current = A
10. D.C. circuits  →  10.2. Kirchhoff’s laws
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6
State what is meant by a field line (line of force) in an electric field. An electric field has two different regions X and Y. The field strength in X is less than that in Y. Describe a difference between the pattern of field lines (lines of force) in X and in Y. A particle P has a mass of 0.15 u and a charge of −1e, where e is the elementary charge. Particle P and an α-particle are in the same uniform electric field. Calculate the ratio magnitude of acceleration of particle P magnitude of acceleration of α-particle . ratio = Particle P is a hadron composed of only two quarks. One of them is a down quark. By considering charge, determine a possible type of the other quark. Explain your working.
18. Electric fields  →  18.1. Electric fields and field lines
20. Magnetic fields  →  20.3. Force on a moving charge
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