Page 16 - SP015 Past Years PSPM Chapter 6 -14 Ver 2020
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PHYSICS PSPM SEM 1 1999 - 2017
PSPM 2010/2011 SF017/2 No. 2
9. 120 cm
15 cm
750 N
FIGURE 8.7
A 750 N athlete is doing a push-up exercise by putting his palms and toes on the floor
as shown in FIGURE 8.7. The athlete’s centre of mass is 15 cm from his palms. The
horizontal distance between his toes and palms is 120 cm. Assume the posture of the
athlete as a rigid body,
(a) draw a free body diagram of the athlete. [1 m]
(b) calculate the force acting on each of his palms. [3 m]
PSPM 2014/2015 SF016/2 No. 5(b)
10.
R Q
P
30
FIGURE 8.8
FIGURE 8.8 shows a crane with 8 m uniform arm PQ of mass 2400 kg pivoted at P.
The arm is supported by a horizontal cable QR.
(a) Sketch and label all the forces acting on the arm PQ. [3 m]
(b) Calculate the tension in cable QR. [3 m]
(c) If Q is raised by shortening cable QR, what is the effect to the tension of the
cable? Explain your answer. [2 m]
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