A 250-g block is coasting at 1.5 m/s and collides head-on with another block that is at rest. Right after collision, the two blocks are locked together, traveling at 0.5 m/s. Is the second block heavier than the first block? Justify your answer.

Avehicle has an oil leak that is causing the entire oil pan to be wet, but inspection reveals no exact source after cleaning off the oil residue. technician a says to install a fluorescent dye in the crankcase and operate the engine, then re-inspect for leaks with a special light (black light). technician b says the oil leak may be coming from a source at the top of the engine, such as a valve cover gasket. who is correct?