Calculate the work done by a porter
holding a suitcase weighing 50 kg on
his head

If an athlete runs once around a track, back to the starting line, her average velocity is zero. true or false?

The field lines around one end of a bar magnet are shown below based on the diagram, what can you conclude about the pole of the magnet? a. is a south pole because the field hnes spread out from this end b. a north pole because the field lines spread out from this end c. a nouth pole because the field lines enter the magnet at this end d. is a north pole because the field lines enter the magnet at this end

The largest observatory complex in the world is on mauna kea, the tallest mountain on earth. what are some factors astronomers consider when selecting an observatory site? don’t forget practical ones. should astronomers, for example, consider building an observatory on denali (mount mckinley) or mount everest?