Page 48 - SP015 Past Years PSPM Chapter 6 -14 Ver 2020

PHYSICS PSPM SEM 1 1999 - 2017

PSPM 2017/2018 SF016/2 No. 7(a)

28. (a) How does sound intensity change with distance from a point source? [1 m]

(b) In a longitudinal wave in a horizontal spring, the coils move back and forth in the
direction of wave motion. If the coil speed is increased, does the wave
propagation speed decrease, remain the same or increase? Explain your answer.
[2 m]

Application of Standing Wave ~ Stretched String

PSPM JUN 1999/2000 SF035/2 No. 9

29. A wire with both ends fixed has tension 80 N. Length and mass of the wire are 1.5 m
and 2.0 g respectively. This wire is vibrated at fundamental mode by pulling its centre
about 3 cm.

(a) Explain the difference between the type of wave formed in the wire and the wave
formed in the air due to the vibration of the wire. [2 m]
(b) Draw a diagram to show this wave and mark the nodes and antinodes. [2 m]
(c) Calculate the vibration frequency of the string at fundamental mode. [4 m]
(d) If the distance x of a particle on the wire is measured from the mid point, calculate
the amplitude of the particle at x = +0.5 m. [4 m]
(e) Calculate the displacement at x = 0.5 m at time t = 0.025 s. [3 m]

PSPM 2003/2004 SF017/2 No. 12(d)

30. A string of mass 240 g and length 2.0 m has one of its ends fixed to a wall and the other
end is forced to vibrate transversely with a frequency of 50 Hz. If the string is stretched
to a tension of 140 N, calculate the velocity and wavelength of the wave produced.
[4 m]

PSPM 2005/2006 SF017/2 No. 5(a)

31. A 2 m taut string is plucked at its centre producing vibrations with fundamental
frequency of 40 Hz. Calculate the velocity of the transverse wave propagating in the
string. [3 m]

PSPM 2009/2010 SF017/2 No. 12(b)

32. A rope of mass 0.8 kg is stretched between two supports 20.0 m apart. The tension in
the rope is 100 N. Calculate the
(a) mass per unit length of the rope. [1 m]
(b) time taken for a pulse to travel from one end to the other. [3 m]

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