Two 10cm diameter metal disks separated by a 0.63mm thick piece of pyrex glass are charged to a potential difference of 1000v. dialectric constant for pyrex is k=4.7. what is the surface charge density on the disks?

Abus travels 280km south along a straight path with an average velocity of 88km/h to the south. the bus stops for 24 min, then it travels 210 km south with an average velocity of 75 km/h to the south. how long does the total trip last?