Two blocks are connected by a very light string passing over a massless and frictionless pulley. Fig#$1.$

Traveling at constant speed, the $20\mathrm{.}0-N$ block moves $75\mathrm{.}0cm$ to the right and the $12\mathrm{.}0-N$ block moves

$75\mathrm{.}0cm$ downward. How much work is done?

a$)$ On the $12\mathrm{.}0-N$ block by i$)$ gravity and ii$)$ the tension in the string?

b$)$ How much work is done on the $20\mathrm{.}0-$ N block by i$)$ gravity, ii$)$ the tension in the string,

iii$)$ friction, and iv$)$ the normal force?

c$)$ Find the total work done on each block.