1. 1. A spherical concrete block with volume of 0.025 m
3
and weight of 23.5 kN/m
3
, is tied to one end of a wooden post so that the part of the post is exposed above the
water surface. If the dimension of the wooden post is 210 mm by 210 mm by 4000 mm with a weight of 6.42 kN/m
3
, find (a) the length of the wooden post exposed
above the water surface.
(b) If it is desired to make the top of the wooden post flush with the water surface, how much weight of the spherical concrete block is required.

2.
2. A 180 mm by 180 mm by 4000 mm timber beam with a unit weight of 750 N, is shown in the figure below, find (a) the length of the beam submerged in water, (b) the
angle θ and (c) the height of water required when the timber beam will stand vertically.
SOLUTION: