Page 47 - SP015 Past Years PSPM Chapter 1 -5 Ver.2020

PSPM SP015

UPS 2001/2002 SF015 No. 4(c)

14. A 5 kg mass at rest moves a distance of 2 m when a constant force of 10 N is applied in
the direction of displacement of mass. Calculate the final velocity of the mass using
work-energy theorem. [3 m]

PSPM 2001/2002 SF015/2 No. 2

15. Y

50 kg 300 cm
F
X
400 cm

FIGURE 5.6

FIGURE 5.6 shows a horizontal force, F pushing a safe of mass 50 kg on a smooth
inclined plane from position X to position Y. If F is 400 N, calculate
(a) the work done to move the safe (in joule). [2 m]
(b) the potential energy at position Y. [2 m]

UPS 2005/2006 SF017 No. 4

16. F

47

FIGURE 5.7

FIGURE 5.7 shows a block of mass 60 kg pulled by a constant force, F = 200 N on a
rough surface at an angle 47 to the horizontal. The frictional force between the block
and the surface is 70 N. If the block moves 50 m horizontally, determine the net work
done on the block. [5 m]

PSPM 2005/2006 SF017/2 No. 2

17. A 10.0 J of work is needed to stretch an elastic spring by 2.0 cm. Calculate the work
required to further extend the spring to 5.0 cm. [4 m]

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