Page 15 - SP015 Past Years PSPM Chapter 6 -14 Ver 2020
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PSPM SP015
PSPM 2006/2007 SF017/2 No. 11(b)
7.
0.3 m
2.4 m
FIGURE 8.5
FIGURE 8.5 shows a uniform plank, 4.0 m long and mass 6.0 kg, supported by two
sawhorses, at 0.3 m and 2.4 m from its right end. A 2.5 kg cat walks on it from right to
left until a certain position where the plank just begins to tip.
(a) Draw all the forces acting on the plank when it just begins to tip. [4 m]
(b) Calculate the position of the cat from the left sawhorse when the plank just begins
to tip. [2 m]
PSPM 2007/2008 SF017/2 No. 2(a)
8.
ladder smooth
wall
rough floor
FIGURE 8.6
A uniform ladder is at rest on a rough floor and leaning against a smooth wall as shown
in FIGURE 8.6. Sketch a free body diagram showing THREE forces acting on the
ladder. [3 m]
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