A toy truck T at rest, has a hemispherical trough of radius R in it [O is the centre of the hemisphere]. A small block A is kept at the bottom of the trough. The truck is accelerated horizontally with an acceleration a. (i) Find the minimum value of a for which the block is able to move out of the trolley. (ii) If magnitude of a is twice the minimum value found in (i), find the maximum height (measured from its original level at the bottom of the trough) to which the block will rise.
