Page 18 - SP015 Past Years PSPM Chapter 6 -14 Ver 2020

PHYSICS PSPM SEM 1 1999 - 2017

PSPM JAN 2000/2001 SF025/2 No. 1

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15. A bicycle wheel rotates with an angular velocity of 10π rad s . At 3 seconds after that,
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its angular velocity becomes 4π rad s . Calculate
(a) the angular acceleration of the wheel. [2 m]
(b) the time taken for the wheel to stop. [1 m]

PSPM JAN 2000/2001 SF025/2 No. 9(b)

16. A light string is wound the outer surface of a disc of diameter 40 cm. This disc is free to
rotate about an axis at the centre of the disc. The string is then pulled with an
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acceleration of 1.2 m s for 1.8 s.
(a) Calculate the angular speed of the disc at its final period of acceleration. [3 m]
(b) What is the total rotation of the disc through the period of acceleration? [3 m]

PSPM JUN 2000/2002 SF025/2 No. 1

17. A barrel of a washing machine makes 1200 rotations per minute. If the diameter of the
barrel is 35 cm, calculate

(a) the rotating frequency in Hz. [2 m]
(b) the angular velocity of the barrel. [2 m]

(c) the linear speed at the rim of the barrel. [2 m]

PSPM 2004/2005 SF017/2 No. 3

18. A wheel turns about its axis of rotation at uniform angular acceleration from rest to
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reach an angular velocity of 30 rad s in 20 s. Calculate
(a) its angular displacement after 4 s. [2 m]

(b) its tangential acceleration at a point 12 cm from the axis of rotation. [2 m]

PSPM 2006/2007 SF017/2 No. 3

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19. A spinning top has an initial angular velocity of 35 rad s . After 0.6 s, the angular
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velocity decreases to 33 rad s . Assuming a uniform angular deceleration, calculate
(a) the angular deceleration. [2 m]
(b) the number of revolutions during the 0.6 s interval. [2 m]

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