our friend Bob is riding on a skateboard with velocity w relative to the lab, while observing the same experiment. Will Bob also think that momentum is conserved

What is the function of the commutator in a dc motor? a. to spin the magnet b. to change direct current into alternating current c. to change alternating current into direct current d. to spin the wire coil

Which type of microscope would allow the viewer to see ribosomes inside a cell?

Road users moving into your lane, brake lights, and abrupt changes in road surface are a. rare at night b. indicators of potential hazards c. not worth worrying about before you reach them d. no problem for experienced drivers