9702_w17_qp_21
A paper of Physics, 9702
Questions:
8
Year:
2017
Paper:
2
Variant:
1
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1
The drag force FD acting on a sphere moving through a fluid is given by the expression FD = Kρv 2 where K is a constant, ρ is the density of the fluid and v is the speed of the sphere. Determine the SI base units of K. base units A ball of weight 1.5 N falls vertically from rest in air. The drag force F D acting on the ball is given by the expression in . The ball reaches a constant speed of 33 m s–1. Assume that the upthrust acting on the ball is negligible and that the density of the air is uniform. For the instant when the ball is travelling at a speed of 25 m s–1, determine the drag force F D on the ball, FD = N the acceleration of the ball. acceleration = m s–2 Describe the acceleration of the ball in as its speed changes from zero to 33 m s–1.
3. Dynamics  →  3.2. Non-uniform motion
4. Forces, density and pressure  →  4.3. Density and pressure
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2
The variation with time t of the velocity v of two cars P and Q is shown in . v / m s–1 t / s car Q car P The cars travel in the same direction along a straight road. Car P passes car Q at time t = 0. The speed limit for cars on the road is 100 km h–1. State and explain whether car Q exceeds the speed limit. Calculate the acceleration of car P. acceleration = m s–2 Determine the distance between the two cars at time t = 12 s. distance = m From time t = 12 s, the velocity of each car remains constant at its value at t = 12 s. Determine the time t at which car Q passes car P. t = s
2. Kinematics  →  2.1. Equations of motion
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3
State the difference between a stationary wave and a progressive wave in terms of the energy transfer along the wave, the phase of two adjacent vibrating particles. A tube is open at both ends. A loudspeaker, emitting sound of a single frequency, is placed near one end of the tube, as shown in . A A A A tube 0.60 m loudspeaker The speed of the sound in the tube is 340 m s–1. The length of the tube is 0.60 m. A stationary wave is formed with an antinode A at each end of the tube and two antinodes inside the tube. State what is meant by an antinode of the stationary wave. State the distance between a node and an adjacent antinode. distance = m Determine, for the sound in the tube, 1. the wavelength, wavelength = m 2. the frequency. frequency = Hz Determine the minimum frequency of the sound from the loudspeaker that produces a stationary wave in the tube. minimum frequency = Hz
7. Waves  →  7.1. Progressive waves
8. Superposition  →  8.1. Stationary waves
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5
Three cells of electromotive forces (e.m.f.) E1, E2 and E3 are connected into a circuit, as shown in . X Y W Z I3 I2 I1 E3 E2 E1 R4 R1 R3 R2 The circuit contains resistors of resistances R1, R2, R3 and R4. The currents in the different parts of the circuit are I1, I2 and I3. The cells have negligible internal resistance. Use Kirchhoff’s laws to state an equation relating I1, I2 and I3, E1, E3, R1, R3, R4, I1 and I3 in loop WXYZW, E1, E2, R1, R2, I1 and I2 in loop YZWY.
10. D.C. circuits  →  10.2. Kirchhoff’s laws
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6
Define electric field strength. Two parallel metal plates in a vacuum are separated by a distance of 15 mm, as shown in . metal plate metal plate 15 mm particle mass 1.7 × 10–27 kg charge +1.6 × 10–19 C + – A B A uniform electric field is produced between the plates by applying a potential difference between them. A particle of mass 1.7 × 10–27 kg and charge +1.6 × 10–19 C is initially at rest at point A on one plate. The particle is moved by the electric field to point B on the other plate. The particle reaches point B with kinetic energy 2.4 × 10–16 J. Calculate the speed of the particle at point B. speed = m s–1 State the work done by the electric field to move the particle from A to B. work done = J Use your answer in to determine the force on the particle. force = N Determine the potential difference between the plates. potential difference = V On , sketch a graph to show the variation of the kinetic energy of the particle with the distance x from point A along the line AB. Numerical values for the kinetic energy are not required. kinetic energy x / mm
18. Electric fields  →  18.5. Electric potential
18. Electric fields  →  18.2. Uniform electric fields
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7
Define the ohm. Wires are used to connect a battery of negligible internal resistance to a lamp, as shown in . wire wire The lamp is at its normal operating temperature. Some data for the filament wire of the lamp and for the connecting wires of the circuit are shown in . filament wire connecting wires diameter d 14 d total length L 7.0 L resistivity of metal (at normal operating temperature) ρ 0.028 ρ Show that resistance of filament wire total resistance of connecting wires = 1000. Use the information in to explain qualitatively why the power dissipated in the filament wire of the lamp is greater than the total power dissipated in the connecting wires. The lamp is rated as 12 V, 6.0 W. Use the information in to determine the total resistance of the connecting wires. total resistance of connecting wires = Ω The diameter of the connecting wires is decreased. The total length of the connecting wires and the resistivity of the metal of the connecting wires remain the same. State and explain the change, if any, that occurs to the resistance of the filament wire of the lamp.
9. Electricity  →  9.3. Resistance and resistivity
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