A negatively charged metal ball of negligible mass is separated from a negatively charged

Question

rectangular block (assume the charge cannot escape) by an initial linear distance ‘d’. On the other
side, the metal ball sits at the start of a semicircular loop of radius’R’, made of wood.
Task a. Find the field due to the charged rectangular block and at what distance from the ball the
ball enters the field of the block to experience a force to just move the same (neglect friction).
Task b. As the block moves towards the ball with a constant velocity ‘v’,find an expression for
the velocity which will enable the ball to rise to the top of the loop.
Task c. As the block moves towards the ball with a constant acceleration ‘a’, find an expression
for the ‘a’ which will enable the ball to rise to the top of the loop.
Task d. calculate the charge and dimensions of the block for which the ball will be driven to the
centre of the semicircle without moving the block.