Two blocks with masses m and 3m are attached to the ends of a string with a negligible mass that passes over a pulley. The pulley has a negligible mass and friction and is attached to the ceiling. The blocks are simultaneously released from rest.
Derive an equation for the speed v of the block of mass 3m after it falls a distance d in terms of m, d, and physical constants?

Consider a production line with five stations. station 1 can produce a unit in 9 minutes. station 2 can produce a unit in 10 minutes. station 3 has two identical machines, each of which can process a unit in 12 minutes (each unit only needs to be processed on one of the two machines. station 4 can produce a unit in 5 minutes. station 5 can produce a unit in 8 minutes. which station is the bottleneck station?