Figures 1 shows a tower crane with the properties listed in Table 1. The distance between the trolley and mast x can change from 0 to dj (Figures 1 and 2).

Draw the free body diagram of the tower crane and calculate the reactions at O when the mass of the lifted body = 5000 and the distance = 20 m.

Table 1: Specifications of the tower crane (See Figures 1 and 2 for definition of each specification)

Counter-weight mass	=1000(600.1) kg
Counter-jib length	=12 m
Mass of counter-jib	1=8000
Centre of mass of counter-jib	G1
Length of jib	=4015 (m)
mass of jib	2=32000 kg
Centre of mass of jib	G2
Height of mast	=40 m
Mass of mast	3=48000
Centre of mass of mast	G3

1 counter-weight 5 trolley 2 counter-jib 6 hook block 3 mast 7 lifted body 4 jib Figure 1: A tower crane (left) and its model (right). Figure 2: Tower crane specifications (See Table 1 for values of these specifications) 1 counter-weight 5 trolley 2 counter-jib 6 hook block 3 mast 7 lifted body 4 jib Figure 1: A tower crane (left) and its model (right). Figure 2: Tower crane specifications (See Table 1 for values of these specifications)