Page 56 - SP015 Past Years PSPM Chapter 6 -14 Ver 2020

PHYSICS PSPM SEM 1 1999 - 2017

PSPM 2004/2005 SF017/2 No. 6

9.

0.2 m

10.0 kg

0.2 m

5.0 kg

FIGURE 11.3

FIGURE 11.3 shows a 10.0 kg weight suspended by a 0.2 m vertical copper wire with
2
cross-sectional area 5 mm . A 5.0 kg weight is suspended by a similar wire from the
bottom of the 10.0 kg weight. Calculate

(a) the strain of each wire. [2 m]

(b) the extension of each wire. [2 m]

11
-2
(Young’s Modulus of copper is 1.10  10 N m )

PSPM 2006/2007 SF017/2 No. 13(c)(ii)

10. A wire of length L and cross-sectional area A elongates by e when a tensile force F acts
on it. If k and Y are the force constant and the Young’s modulus of the wire,
respectively, obtain an expression for k in terms of Y. [3 m]

PSPM 2008/2009 SF017/2 No. 6

2
11. A 4.0 m iron rod with cross-sectional area 0.5 cm extends by 1.0 mm when a 225 kg
mass is suspended from one of its ends. Calculate the

(a) Young’s modulus of the rod. [2 m]

(b) elastic energy stored in the rod. [2 m]

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