A gravity dam is built across a river to store water in a reservoir. Engineers have designed the masonry wall so that it is much broader at the base than at the top.
(a) Define (i) thrust and (ii) pressure.
(b) Explain why the wall must be broader at the base than at the top, using the ideas of thrust and pressure on the wall. Do not refer to any relation involving depth of the water.
(c) The area of the wall surface in contact with water at the base is 200m2. If the total thrust on this portion is 4.0×106N, calculate the average pressure acting there.