9702_m16_qp_22
A paper of Physics, 9702
Questions:
6
Year:
2016
Paper:
2
Variant:
2
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1
The speed v of a transverse wave on a uniform string is given by the expression v = T l m where T is the tension in the string, l is its length and m is its mass. An experiment is performed to determine the speed v of the wave. The measurements are shown in . quantity measurement uncertainty T l m 1.8 N 126 cm 5.1 g ± 5% ± 1% ± 2% State an appropriate instrument to measure the length l. Use the data in to calculate the speed v. v = m s−1 Use your answer in and the data in to determine the value of v, with its absolute uncertainty, to an appropriate number of significant figures. v = ± m s−1
1. Physical quantities and units  →  1.3. Errors and uncertainties
7. Waves  →  7.1. Progressive waves
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2
Define acceleration. A ball is kicked from horizontal ground towards the top of a vertical wall, as shown in . 28° path of ball ball wall horizontal ground v 24 m (not to scale) The horizontal distance between the initial position of the ball and the base of the wall is 24 m. The ball is kicked with an initial velocity v at an angle of 28° to the horizontal. The ball hits the top of the wall after a time of 1.5 s. Air resistance may be assumed to be negligible. Calculate the initial horizontal component vX of the velocity of the ball. vX = m s−1 Show that the initial vertical component vY of the velocity of the ball is 8.5 m s−1. Calculate the time taken for the ball to reach its maximum height above the ground. time = s The ball is kicked at time t = 0. On , sketch the variation with time t of the vertical component vY of the velocity of the ball until it hits the wall. It may be assumed that velocity is positive when in the upwards direction. 0 0 5.0 –5.0 –10.0 10.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 t / s vY / m s–1 Use the information in to determine the maximum height of the ball above the ground. maximum height = m The maximum gravitational potential energy of the ball above the ground is 22 J. Calculate the mass of the ball. mass = kg A ball of greater mass is kicked with the same velocity as the ball in . State and explain the effect, if any, of the increased mass on the maximum height reached by the ball. Air resistance is still assumed to be negligible.
2. Kinematics  →  2.1. Equations of motion
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3
State what is meant by work done, elastic potential energy. A block of mass 0.40 kg slides in a straight line with a constant speed of 0.30 m s−1 along a horizontal surface, as shown in . 0.30 m s–1 block mass 0.40 kg spring The block hits a spring and decelerates. The speed of the block becomes zero when the spring is compressed by 8.0 cm. Calculate the initial kinetic energy of the block. kinetic energy = J The variation of the compression x of the spring with the force F applied to the spring is shown in . 8.0 x / cm FMAX F Use your answer in to determine the maximum force FMAX exerted on the spring by the block. Explain your working. FMAX = N Calculate the maximum deceleration of the block. deceleration = m s−2 State and explain whether the block is in equilibrium 1. before it hits the spring, 2. when its speed becomes zero. The energy E stored in a spring is given by E = 1 2 k x 2 where k is the spring constant of the spring and x is its compression. The mass m of the block in is now varied. The initial speed of the block remains constant and the spring continues to obey Hooke’s law. On , sketch the variation of the maximum compression x0 of the spring with mass m. x0 m
6. Deformation of solids  →  6.1. Stress and strain
6. Deformation of solids  →  6.2. Elastic and plastic behaviour
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4
By reference to the direction of propagation of energy, state what is meant by a transverse wave. State the principle of superposition. Circular water waves may be produced by vibrating dippers at points P and Q, as illustrated in . Q R wavefront P 44 cm 29 cm (not to scale) The waves from P alone have the same amplitude at point R as the waves from Q alone. Distance PR is 44 cm and distance QR is 29 cm. The dippers vibrate in phase with a period of 1.5 s to produce waves of speed 4.0 cm s−1. Determine the wavelength of the waves. wavelength = cm By reference to the distances PR and QR, explain why the water particles are at rest at point R. A wave is produced on the surface of a different liquid. At one particular time, the variation of the vertical displacement y with distance x along the surface of the liquid is shown in . 0 0 1.0 –1.0 –0.5 0.5 y / cm x / cm The wave has intensity I1 at distance x = 2.0 cm and intensity I2 at x = 10.0 cm. Determine the ratio intensity I2 intensity I1 . ratio = State the phase difference, with its unit, between the oscillations of the liquid particles at distances x = 3.0 cm and x = 4.0 cm. phase difference =
8. Superposition  →  8.1. Stationary waves
7. Waves  →  7.1. Progressive waves
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5
State what is meant by an electric current. Define electric potential difference (p.d.). A power supply of electromotive force (e.m.f.) 8.7 V and negligible internal resistance is connected by two identical wires to three filament lamps, as shown in . 0.30 A power supply 8.7 V connecting wires (not to scale) The power supply provides a current of 0.30 A to the circuit. The filament lamps are identical. The I–V characteristic for one of the lamps is shown in . 0.20 0.30 0.10 0.40 1.0 2.0 3.0 4.0 V / V I / A Show that the resistance of each connecting wire is 2.0 Ω. The resistivity of the metal of the connecting wires does not vary with temperature. On , sketch the I–V characteristic for one of the connecting wires. Calculate the power loss in one of the connecting wires. power = W Some data for the connecting wires are given below. cross-sectional area = 0.40 mm2 resistivity = 1.7 × 10−8 Ω m number density of free electrons = 8.5 × 1028 m−3 Calculate 1. the length of one of the connecting wires, length = m 2. the drift speed of a free electron in the connecting wires. drift speed = m s−1
9. Electricity  →  9.3. Resistance and resistivity
9. Electricity  →  9.2. Potential difference and power
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