15. An object is placed 16 cm from a convex spherical mirror of radius -9.0 cm. What type of image forms, and at what distance from the mirror?
real image, 3.5 cm from the mirror
virtual image, 8.9 cm from the mirror
virtual image, 5.8 cm from the mirror
virtual image, 3.5 cm from the mirror

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

Which of these metals are magnetic?

On a mild saturday morning while people are working inside, the furnace keeps the temperature inside the building at 23degreesc. at noon the furnace is turned off, and the people go home. the temperature outside is a constant 16degreesc for the rest of the afternoon. if the time constant for the building is 3 hr, when will the temperature inside the building reach 18degreesc? if some windows are left open and the time constant drops to 2 hr, when will the temperature inside reach 18degreesc?